327: 210hp vs 230hp

[jon_e_quest]

I'm curious to know what CC did to get an extra 20 horsepower when they introduced the 230hp version of the 327 in 1969. Can anyone shed some light for me?

Thanks,
Marc

[Wood Commander]

I might have missed a model in there somewhere, but I think the 327 Q was 210 hp and the 350 Q was 230 hp. The 350 had substantially more torque though. As far as I am aware, the 327 F was always 210 hp. Like I said, I might have missed something in there somewhere!

[Al Benton]

I was in a 1970 17' Corsair Ski Boat at Lake Dora last weekend that I was told has a 327Q. The literature in the archive advertises it as a 230HP. I have no idea how the extra 20HP was achieved though.

Al

[wdnboats1]

Here is what I believe to be the case regarding the 210HP 327F and the 230HP 327Q.

Chevrolet introduced the large journal small block in 1968/69. The 283 and 327F were the small journal blocks, the 327 being a larger displacement 283. The 307, 327, and 350Q were the large journal blocks.

Take a 283 and add longer stroke to get the 327F. (Note - This is why you MUST clearance the cast oil pan when repowering a 283)

Take a 307Q and add longer stroke to get the 327Q.

Take the 327Q and add larger bore to get the 350Q.

Of all of the Q's the 327 had the most torque due to the longer stroke with the smaller bore.

The later (1970's) 350K @ 255HP was a 305K @ 225HP with a larger bore.

Hope this helps - worth about what you paid for it.

Dave Ashley

[DeanS29]

I have a LH(prop), Flywheel back, 327 that according to mortec.com is a 62-67 327. However if I am reading the code correctly (L78) has a casting date of 12-7-1968. The casting code on the heads says they are 1968 70cc 307/327. Is there any way to tell if it is a 283/327 or a 307/327 as referred to in Dave's post? My guess is 283/327 if the heads are interchangeable, which I assume they are, and somebody put a newer set of heads on. Any insights are appreciated. Thanks Dean

[Al Benton]

Dean, we may have to depend on David to reply to that but it's curious why new heads were installed and if other enhancements may have been made too.

I glanced through The Essential Guide and found that every division of Chris Craft started using the 327Q engines, including the 46' Aqua Homes in 1969. That includes the Main Div., Sea Skiff, Cavalier, Corsair, Catalina, Roamer and Commander.

Another fun discovery is that the 1969 Cavalier 17' Ski Boat, hull series KRA-17- was sold as the 1970 Corsair 17' Ski Boat, hull series ORA-17-. It's the same boat.

Marc, you have a 1962 Cavalier 18' Custom with a 283. Will a 327Q fit in there considering the added depth of the oil pan?

Al

[Wilson Wright]

Manifold lable says it is 230 HP also...Not sure what they did over the years to get it up from 210.

[Wood Commander]

This thread has made me curious enough to go dig into my collection and pull out some engine manuals out of the CC engine section to refresh my memory.

OK, first of all we need to know that in the small block Chevy V8 usage, Chris Craft utilized pretty much the same basic car engines in "pretty much" the same version as Chevy delivered them. And no, they were not Corvette engines uness somebody put one in a boat on their own.

Of course there are different sizes and horsepowers. And Chris Craft marinized them into flywheel aft or flywheel forward as they saw the need to do so. But whether they were a flywheel aft "F" or a flywheel forward "Q", they were still the same basic engine. Of course, the cams and cam gear were different on any engines that needed to run "backwards" as compared to a car engine. NOTE, that did not always mean that a backwards (as compared to a car) engine always swung a left handed prop. Being a an F or Q meant all of the difference here. And if you go back to the very first small Chevy 283 Chris Craft installations, they were flywheel aft and I think that they were just called 283's and 283 O's for an opposite rotation engine for the Port side in a twin engine cruiser installation. This was pre "F" or "Q". There might have been flywheel aft 283's in that early time frame, I'm not sure. And somewhere in there I think there was a 283 H, and I presume HO. I'm sure someone on the list knows about the very earliest 283 usage and designations.

As to some of the previous posts, I think that there is some confusion.

I guess you could say that a 327 is a larger displacement 283, but that is true for any larger version of any engine in the same family.

Yes, the 307, 327 and 350 Q's were large journal engines.

No, a 283 is not a longer stroke 327. The bore and stroke of a 283 is 3 7/8" bore X 3" bore. A 327 is a 4.00 bore (same as a 350) with a 3.25" stroke.

No, a 307 with a longer stroke is not a 327. A 307 has a bore size of 3 7/8" X 3.25" stroke (same as a 327).

No, a 327 with a larger bore is not a 350. A 327 has a 4.00 bore (same as a 350) with a 3.25" stroke.

No, the 327 Q was not the highest torque of all the Q engines. The highest torque output Q engine is the 350 Q at 335 ft. lbs. @ 3200 rpm., compared to 328 ft. lbs. @ 3200 rpm. produced by the 327 Q.

In an FLV manual that I found (an FLV meant left hand rotation (same as a car) and hooked to a Volvo outdrive) there was a 302 FLV shown @ 210 hp. @ 5800 rpm. A real screamer for a production boat engine!This appears to be like a Chevy Camaro Z 28 engine and might have been installed in XK 19's or something.

Some people probably know the reason that the Z28 302 engine (4.00" bore X 3.00" stroke) was developed by Chevy. The same reason that Ford developed the Boss 302.
They wanted to go Sports Car Club of America Trans Am racing with the Camaro to compete against the Mustangs, and other "pony" cars. And the rules had a 305 cubic inch displacement limit. So it looks like Chevy took the bore of the 327/350 and mated it to the stroke of the 283. That is a pretty rare engine in car usage and very valuable. It has to be pretty rare in a boat too, but I don't know if it is exactly th same as the Z28 engine.

I've scanned in some manual stuff and will try to post it into a different posting if I have time.

[John DeVries]

Marc,

My guess would be that the 20 HP gain would come through a different cam profile with more duration and lift for the valves, and/or reconfigured combustion chambers in the cylinder heads for better "breathing". Also possibly a small bump in compression.

John

[DeanS29]

The pages from the manuals that Bret posted show the following, Thanks Bret for taking the time to scan all this.

327F 210hp @4000 rpm 8.0:1 compression
327Q 230hp @4200 rpm 8.8:1 compression

Dean

[Wood Commander]

Yes, that pretty much shows that the later Q version of the 327 had a little more compression and a few more hp. Perhaps there were some other small differences. And I had kind of overlooked the fact of that being the original question! In my typical style of thinking- "oh, a 327", means- "210 hp" and automatically assigning that hp to all 327's. Once again, got to tighten up! The devil is in the details!

So now we know that the later Q series of 327's were a little more "perky". Just remember that a complete Chris Craft 327 Q would not be interchangeable with a complete Chris Craft 327 F. But if you found a Q longblock in the appropriate rotation, you could put it in place of an F longblock, using all of the appropriate Chris Craft F hardware in place of the Q stuff, And vice versa. But you would have to make certain to swap out every auxilliary piece that was specific to your application. Or change EVERYTHING, over to the other type of engine.

[vince xk19]

Hello,

Just thought I would chime in on the Chevy/HP topic. Throughout the late 60s until the early 70s motor companies were increasing HP every year as this was the peak of the very competitive muscle car era. The number one way to increase HP was to increase the compression ratio along with advanced timing. On many engines this required the use of high octane fuel to achieve the rated HP, something that was available at the time. Other common HP enhancements included better induction systems /intake manifolds, larger carburetors, more aggressive cams, and larger valves to increase intake and exhaust flow efficiencies. Shortly thereafter the Fed got in on the act and through a combination of stricter emission and safety regulations HP ratings continually declined throughout the 70s with high compression being the first thing to go. The marine industry mirrored these events.

As far as torque goes, it is true that all things being equal the longer stroke would net more torque, something that is usually more beneficial in marine applications than HP. The 350, 327 and the 302 all share the same bore of 4” inches. The stroke is the only thing that changes. With this logic one can conclude the 350, for a performance marine application, was an excellent choice as it has more torque than the others. The 307 and 283 are similar in that they share the same bore of 3.875 and again it’s just the stroke that makes the difference. The 307 would edge out the 283 in torque for the same reason. Sorry if some of this is redundant to a previous post.

From 1971 on Corvette 350 engines were used in all xk19s and xk22s as the 350FLV. These engines are truly the same, coming with the correct heads, intake manifold, compression ratios, HP ratings, and even the Corvette valve covers. Here are a few pictures.

[Wilson Wright]

So if the compression was increased on the later 327's does that mean I need to use higher octaine fuel for better performance on a 230 hp model ?

Not to be argumentative but I've been around ole Chris Crafts for some time and always heard the Corvette engine story was an ole wives tale...and that Chris Craft really used truck engines because of the higher torque.

[evansjw44]

The "Small Block Chevrolet"SBC marine engine used by CC and others has had a long myth about it being a "Corvette" engine. What seem to be true is that these engines were build in Tonawana, NY plnat that also built the 'vette engine. I think the marine version shared some 'vette parts like the steel cranks and forged rods. But more likely they were what someone called a "parts bin" product where the engines were made up of what ever GM had in thier catalog of available SBC parts. Maybe truck heads and manifolds or the like. Cams were probably unique to the marine version.

[vince xk19]

Hello,

On the 327/230HP with only 8.8:1 compression, high octane fuel is not critical. You don't have to use higher octane fuel, but yes with the right timing advance and even with today’s "lower" high octane fuel there would be an increase in output. When it comes to some of the Corvette engines Chris Craft used, the octane requirements are unrealistically high for today’s fuels without adding octane booster or using avgas, as Chris Craft recommended 101 octane for these engines.

Not to be argumentative…

Wilson I would never take it that way. This is a great forum for all to express their thoughts and opinions. This is how we all learn more about these great boats.

The 350FLV is truly a Corvette engine. They were rated anywhere from 300HP up to 350HP. Chevy 350 truck engine never had 350HP, only the Corvette. Although truck engines sound very plausible with their higher torque the reality is they used 350 Corvette engines in the later XKs, from 1971 on. It was all Chevrolet could do to get 350HP out of the 350 small blocks so it would seem very unlikely that off the shelf parts would achieve such power ratings. It would take a well engineered highly focused effort to net such results back in 1971. I agree with evansjw44 that it is possible the cams may have been altered for marine use, although I have nothing to support this, it makes sense. There are other 350 engines Chris Craft used in many other boats and I suspect they could have been truck blocks. Truck blocks often times used 4 bolt mains and had excellent torque as Wilson points out, making them a great choice for performance, reliability and the demands of marine use.

Vince

[Peter XK19]

Hi,
Just got my 1970 XK-19 and this manual printed in 1971 came with it. Its an operators manual so it doesnt say much, but anyway.......







Peter
www.xk19.com

[Wood Commander]

First, I need to back up a bit here. I found a mistake in one of my earlier posts to this thread. I stated that the earliest Chris Craft/Chevy 283 applications that were just called 283's or 283 O's for opposite rotation, were flywheel aft. Actually I meant just the opposite, they were flywheel forward.

Now about the Corvette engine thing, I think we are both right sort of.

Sometimes it's hard for me to shift around to all of the different eras and types of Chris Craft boats in my mind. Chris Craft is an old company that started building what I call the "traditional Chris Craft construction" of the Carvel planked, batten seam, double bottom mahogany plank" method, as the Smith family boat building business.
But by the end of the company's wooden boat era in 1972, they had been through several different ownerships and were not only building boats in the traditional solid mahogany plank method, but also out of Mahogany or fir plywood, lapstrake planks(Sea Skiff), plywood sheets (Cavalier), Aluminum and steel (Roamer) and Fiberglass (Commander and Corsair Division). And they were building these different constructions in both small runabout- type boats as well as larger cabin cruisers, and all of it at the same time! Pretty amazing when you think about it. Truly a very diverse product line.
But the engines often crossed over to many of the different lines, having been produced by the engine division.

Now even though I own examples of two very different eras of the Chris Craft company's products, built out of materials from opposite spectrums (solid mahogany plank and fiberglass), I tend to mainly think of a Chris Craft as a planked mahogany cruiser. This is because of my background and upbringing on them. But this is not the same experience that many other people have with Chris Craft boats. I love them all, and they are all very special craft.

So when I consider a topic such as "Corvette engines", I kind of automatically default to- "wooden hull, 283 F or 327 F" And it is here that I am most used to seeing people wrongly describing their boat's engine as "being a Corvette engine". I saw this as a youth back in the day, and I have seen people advertising wooden- hulled Chris Craft boats in this manner presently. And that is wrong. Wilson, this is where we say that the Corvette engine is an old wive's tale.

But now we see where Vince seems to have found a Corvette engine in an XK 19. But this is apparently a 350, not the 283/327 that I am used to talking about. So this is a different, newer period in Chris Craft history, and I am thinking, a fairly rare occurrance.

So I have learned something here. I believe that Vince is correct because if you look at the last scan in my post "Chris Craft- small block Chevy V8 Manual Info", you see a 1972 Chris Craft Engine Division dealer price sheet for selling engines to customers sans boat.

On this sheet it shows a 350 QLV, 235 hp for $3,550.00. This would be the Q(L) engine that mates up to a Volvo outdrive (I wonder if the outdrive was included for that price? A 350 Q bobtail went for $2,250.00 and a 350 Q with a transmission hovered around $2700.00). This setup is the type that was found in Corsair Division Lancers, XK's and others.

But this sheet also shows a 350 "High Performance" 350 hp engine (and a Volvo note) at 350 hp for $4110.00 (it doesn't say 350 QLV, but this was probably typed and printed out at the dealer office, not from the factory. But there should have been some kind of special designation.).
This definately looks like a super performance XK power option and would appear to be the Corvette engine.
Vince do you have the engine numbers and date codes off of the back of the Corvette boat block, or the stamped numbers off of the right front block pad just under the head/block parting line? And have you ever cross checked them against Corvette car numbers? I'd love to know how they parse out!

Now I have to note that in one of Vince's pictures it looks like it says "Marine Power" on the manifold. So I have to wonder if this was the beginning of the newer, slightly different and slightly less "pure" Chris Craft engine supply source. I believe that marine Power was tied to Chris Craft, but was not actually the original engine division. From what I have seen the Marine Power/Chris Craft engines had many more generic parts than what I am calling the pure Chris Craft engine division products. I would be very interested in hearing from anybody that knows the Marine Power era story. From what I can tell it was a kind of transition era into the Scorpion runabout age where Mercruiser drivetrains were used in Chris Craft boats, at least in the Sportboats.

And Pete, that looks like the same manual that I had scanned in that other post. Did you notice what I think is a mistake in the 302 FLV specifications? Under cubic inch, it says- 310 cubic inch? I think they had the 310 hp on their mind and transposed that down to the cubic inch line as well instead of 302 cubic inch.

Anyway, if anybody ever sees an XK 19 or XK 22 with the 302 FLV in it, I'd like to hear about it! It's got to be pretty rare.

[Peter XK19]

Wood Commander,
I didnt notice the error you mentioned but that is ofcourse just a plain mistake from the author of the manual.
When I bought my latest 1970 XK-19 I felt pretty sure it had the 350 FLV. I thought I asked and I never saw the boat prior to shipping.
But judging from the factory sheet its obvious it came with a 302 FLV. I am pretty sure its the original engine in it. I will check it out as soon as.


Peter
www.xk19.com

[vince xk19]

Wood Commander, excellent follow up. I'm sure a lot of people in the past have thought they had Corvette engines in the earlier boats. I agree, I don't think those were truly Vette engines. I understand what you mean when you were thinking more of the older wooden boats with 283s or 327s. After all that is what many Chris Craft fan are referring to.

I, like Peter have a 1970 XK19 that also has the 302FLV in it. I have not used it yet but it appears to be all there and the engine was said to be running when I bought it. I will post here with updates.

I am also curious about the Marine Power Engines and would love to learn more about them. I just purchased a very nice Marine Power/Chris Craft 350 engine that came out of a factory Chris Craft installation. All the parts look identical. The tags on the exhaust manifold seem to be the only things that changed. Perhaps they renamed the division for some business reason? Maybe they wanted to sell engines to other companies and the new name was needed? I don’t know… like you said, if anyone knows the story let us know.

Peter I will catch up with you soon and we can compare notes. My hull is number ORCZ 19 0022.

Vince

[Wilson Wright]

Bet Jim Wick will know....and he usually responds

WWW

[evansjw44]

A good friend of mine ordered a new '71 'vette with the 350HP 350 CID LT1 engine. The car was a screamer. You could dump some of the smog equip and get more a lot more out of it. But it was a solid lifter cam that needed to rev to 6500RPM to get there.

So I wonder if the XL-- had the 'vette engine, was it an LT1? The standard 'vette engine in 70 and '71 was rated at around 280 HP. When you limit the LT1's revs to marine style applications did that de-reate it a bit?

I'm really curious.

As an aside, my friend's '71 LT1 'vette (very valuable car) sits in his garage waiting for him to get around to putting n a new radiator. By now it needs brakes too. He still has the original exhaust and all the smop parts. Maybe his estate will sell it to low bit in the future.

[J. William Tarbrake]

WOW...what a great and informative discussion. I am especially impressed with WOOD COMMANDERS expertise on this topic. I have a follow up question regarding my engines which I will now post as a new topic in engines and power train. I hope to get a response from wood commander.
BILL

[Wood Commander]

Vince and Pete, you may have really rare engines in those 320 FLV's! If they started out life as Chevy Z 28 302's, you may be very lucky.

When I first saw my manual with the 302 listed, I had to wonder if maybe it meant it was a Ford 302, a much more common engine. But the specs and info on common characteristics on the 302 FLV and the 350 FLV in the manual makes me think that they are indeed Chevy engines. I only wondered about the Ford idea because I had never heard of anybody using a 302 in any Chevy application other than for a Z 28 Camaro in a production vehicle.

Let's definitely verify that your engines are actually Chevy's first. After that, I suppose that it is possible that they might be "parts bin" 302's, but with those performance specs, over 1 hp per cubic inch (I can remember when that was a lofty goal for a production car engine) and a 5,800 rpm redline, I highly doubt it. Take a look on the information pad on the right front corner of the engine block, right at the parting line for the head and block at the front base of the right side head (looking forward from the flywheel end of the engine). A Z 28 engine would have an engine code of "DZ" and some numbers here I believe. I don’t know if a “real” Z 28 engine meant to be sold to another company for installation in another type of vehicle and not intended to be installed in a Camaro would have the DZ designation or not. Or if they ever actually did it. This is a mystery!

If you have a Z 28 engine, it is a very special thing, much more special than even a Corvette engine. And here is why.

As I mentioned before, Chevy needed an engine that would qualify for Sports Car Club of America's Trans Am racing series. This is the series that General Motors paid a royalty to the SCCA for the right to use the Trans Am name on the high performance Firebird models. Ironically, the Firebird was never a major player in the racing series. But Mustangs and Camaros were! This was yet another factory playground in the serious battle for the age- old bragging rights between Ford and Chevy, and especially for their somewhat new small, sporty models.

But the SCCA Trans Am cubic inch limit was 305 cubic inchs, and Chevy didn't have a proper performance engine in this size range. Thus the option code Z 28 was born for the Camaro only, and a legend soon followed. The factory hp rating for the first Z 28 Camaros's in 1967 was 290 hp. The cars had many go fast goodies including four wheel disc brakes and exhaust headers thrown in the trunk for the dealer to install if the customer wanted. Ford also joined in with the Boss 302 Mustang for the same reason. There had to be a certain number of cars built and sold to the general public in order for the racers to be legal contenders, probably about at least 500 units to satisfy the SCCA . But they didn't build too many more than that at first.

Things got interesting with Mark Donahue in Roger Penske's factory backed Sunoco blue Camaro going at it tooth and nail against Parnelli Jones in Bud Moore's Factory mustard yellow Boss 302 Mustang. Both cars had many victories with Chevy winning the Championships in 1968 and 1969 and Ford winning the 1967 and 1970 Championships. The American Motors Javelin won in 1971 after Penske and Donahue had come on board with AMC in 1970.

Donahue zinged the little Z 28 mercilessly in 1968 and 1969 as he sliced through the corners of the circuit road courses with great precision and determination while “Old Rufus” (Parnelli) manhandled the notoriously weak low- end- torqued but Kamakazi- like top ended Boss 302 Mustang at high speed through the corners, exiting sideways and with smoking tires much of the time. And they leaned on each other “occasionally” too.


In 1970, the SCCA relaxed the rules to where even though the race cars had a 305 cubic inch limit, the production versions did not have to hold to that standard. This allowed Chrysler to join the fray with the 1970 AAR Cuda fielded by Dan Gurney and his All American Racers, and Dodge with the Challenger TA fielded by Auto Dynamics and driven by Sam Posey. And American Motors gained the services of Penske and Donahue for the 1970 season. The Chrysler cars had a very good high performance 340 installed in them for normal street production and these are some of the most valued Mopar collectible cars.
Chrysler only produced a 305 for the race track versions of these models in order to be legal for the actual racing.
But while the Penske/Donahue Javelin effort produced wins and good results, the Chrysler entries were not a huge factor in the series and never scored a victory in the 1970 season.

Back in the real world, in 1970 ½, the new, second generation Camaros and Firebirds were introduced. But the new Camaro Z 28 had an LT 1 350 cubic inch engine. These early models are noted for their smaller rear deck lid spoiler much like the spoilers on the first generation Camaros. Later second generation Camaros got the larger 3- piece blade spoilers.

This is why the early DZ 302 equipped Camaros are so highly prized. The three years of the first generation Camaro Z 28’s are the only ones with the special production 302 engine. That is why I am so surprised to see that they may have been installed in boats!
There are many later generation Z 28 Camaro models, but none of them have the legendary DZ 302. So any real DZ code Z 28 Camaro from 1967 to 1969 is a very rare and desirable collector car.

To give you a little better idea of how rare early 302 Z 28’s are, look at their production numbers compared to Chevy’s other “special” car, the Corvette. This isn’t a totally accurate comparison because Corvettes had several different engine options whereas the Z 28 only had the one. But it’s still interesting.


1967-

Z 28 602 out of a total of 220,906 Camaros built

Corvette 22,940 built


1968-

Z 28 7,199 out of a total of 235,147 Camaros built

Corvette 28,566 built


1969-

Z 28 20,302 out of 243,085 Camaros built

Corvette 38,762 built


You can compare this to the production of Chevy’s “family car”, the Impala, for 1969 at 770,000 units. Quite a difference!

So when you watch the Barret-Jackson car auctions on TV and see the price that Z 28’s and Corvettes go for, it might be true that your boat engine is worth many times what your boat is worth! Of course you guys with the nicely restored XK 19’s have quite a nice and collectable boat there too. Maybe someday we’ll see something like Barret-Jackson for boats, or boats at Barret- Jackson. Either way, cool beans!

Let us know what you find with your engine codes guys, I can hardly stand the suspense! This REALLY interesting.

[Wood Commander]

The Z 28 production numbers didn't come through so good on Boat Buzz. I had it typed in better when I wrote it but things ran together in the posting.

So it was supposed to say.........

1967 Z 28- 602 built

1968 Z 28- 7,199 built

1969 Z 28- 20,302 built

let's see how that works.

Also, I forgot to mention, did you notice that on my price sheet there was the 350 FLV 235 hp and the 350 FLV 350 hp engine that we think is the Corvette engine. But there is no 302 FLV listed. I bet it was a very low production for Chris Craft.

[vince xk19]

Hello,

They are definitely Chevy engines, in fact the whole reason I got into the xk19 to this extent was due to this curious engine. What I mean by this extent is, starting the xk19 registry at xk19.net . We currently have about 30 xk19s registered, and a number of other boats tracked. I also owned a 69 Z/28 in my youth. I have been researching this xk19 variant for quite some time and Peter is the first person who has another one. He and I can now compare notes. Hopefully I will be conversing with him soon and we can do a little discovery.

Vince
[email protected]

[Peter XK19]

Hey I got som pics from my 302 FLV engine.
I would say it is very much the boats original engine.

I also found out the entire deck of the boat has lost its original shape from just beeing old I guess. Its become kind of flat in lots of places. My intention for this boat was to go with the original as far as possible in restoring it. But now Im thinking of replacing the deck like I did on my other 1970 XK-19. That boat was a total wreck when I bought it so I knew no one could accuse me for ruining a peice of Chris-Craft history.

Peter

www.xk19.com

[Wood Commander]

Hmmm..... Doesn't look like DZ does it? From looking around on the internent, it looks like the V means the engine was built in Flint, MI (as opposed to a Flint, MI "motor" which was an F, I have no idea what all that means??????????).

The 03 14 might mean March 14th, but the year is still a mystery and the 9BN (that is a 9 isn't it? 1969? BN?)is still unknown. Most of the codes shown on information pages have three letters instead of two. That might indicate that the engine was made for something other than a car installation, such as selling seperately and not in a vehicle.
Do you have the date codes from the right rear angled part of the block? Oh, and you might as well get the casting numbers from the left rear angled part of the block while your looking around there. And where was that other number close to that nut in the picture located at? I can't quite figure out the location!

If I can find my small block chevy numbers book that is buried deep down in my stuff somewhere, I'll look it up. Or if I get by the Chevy dealer I'll stop in and ask about it.

Thanks for posting the pictures, I'm still very interested in finding out about the 302 installation.

It's too bad about the deck warping on your boat. My 1970 23' Lancer has a beam across the underside of the foredeck. I've seen the older 1966-67 23' Lancers with the different shaped deck that have kind of collapsed and warped downward. They were kind of famous for that around the front sliding hatch. This caused the two sides of the windshields to fall in towards each other making the folding center windshield section bind up and jam in together with the outer windshields.

[Wood Commander]

Pete and Vince, I finally got a little more info on the 302/Z-28 engine mystery, but there is more to be known! I hope someday an old Chevy high performance guru will come across this.
I finally got some stuff together and went down to one of the two local Chevy dealers' parts counter looking for a couple of parts as well as trying to find out more about the boat engines. It's funny how life works sometimes. I have dealt with both of these dealerships in the past and have had good experiences. But this time I drew an absolute blank at the first dealer, both in my quest for parts and for the boat engine information. But at the second dealership, I had much better luck. I guess it depends on how busy the countermen are, their frame of mind that day, what you say to them and how interested you can get them in your project of the day, or maybe what kind of long term busy work their boss has given them to accomplish in their "spare" time between customers. Anyway, the second dealer fixed me up for the parts I was after, a stainless exhaust valve and keepers for a Vortec head, and some special Vortec intake manifold bolts out of the GM Performance Parts Manual as well as some engine information out of an old manual.

Here's what I have found out so far about the Chevy DZ Z-28 and the Chris Craft 302 FLV. It's not really too much, but we are making a little progress in this mystery! I'm going to add pictures that I will attempt to match up with the chronological text in my post.

I started out looking up the Camaro Z-28 302 in my 1969 Motors Manual. This is an excellent manual and is truly old school. This is the old fashion way of looking up your engine (not casting) numbers by the 2 or 3 letter suffix. There is also a grill identification chart for each car manufacturer showing pictures of actual car grills. So cool! My Father bought this manual and an old Chilton's manual for me for a Birthday gift many years ago. At the time I wasn't too impressed, no color pictures and even then they looked old fashioned and boring. Wrong! They are a wealth of information! I don't think Dad ever knew how much I really ended up being impressed and how thankfull I was with for his gift. He's gone now, but I still say to myself, thanks Dad! I actually thanked him then, but it wasn't until later that I really came to appreciate the manuals. I wish I would have made a bigger deal of it back then.
So the first pictures are from the Motors manual and the Chilton's manual. I had to use the Chilton book for the actual DZ info because the Motors book had the information in the fold of the book and I couldn't get a good scan of it.

The next 2 pictures are the sheets from the old Chevy dealer manual. The first is a general information sheet showing a legend for the letter codes. The second is a casting identification manual that shows the 9BN code, as from the pictures of the 302 FLV boat engine.
So it shows up as an engine, not serviced under replacement policies (warranty I guess?) and with no service code. So this seems to me to be an engine that Chevy never expected to see again at a dealership for either service or warranty replacement. It makes me think that it was probably sold much like an industrial powerplant to be used in a piece of equipment built by a totally different manufacturer and given another identity and warranty through this second party. Like a boat and engine manufacturer maybe? So it looks like it wasn't given an identification for a Chevy car model, no Z-28 DZ code.

Lastly is information from my copy of Cars & Parts Magazine's "Catalog of Chevy V-8 Engine Casting Numbers 1955-93". The first page shows a casting number from the left rear of the block, where it is slanted at an angle right above where the bellhousing bolts on. It shows casting #'s 3892657 and 3914678 could have been used as Z-28 blocks. The next picture (and page) shows that blocks numbered 3956618 and 3970010 could also be Z-28 engines. I do know that the 3970010 is a good number for 350 blocks. But the large journal 302, 327 and 350 could all use this block with the same bore size, only the stroke lengths and piston wrist pin heighths were different

So at the moment it looks like the casting numbers are going to be our next greatest clue to the story of the engine in your picture. And if that number was the 3956618 casting, it would probably be the most conclusive. Also, the date code numbers are in this same location on the right side, these would help pin down the time frame of the casting.

[Wood Commander]

Oh, and on the Chilton's sheet showing the DZ 302 information, the asterick by the 1969 DZ notation refers to this note- CNA=late production. So it looks like if you had a Z-28 engine built in late 1969 it may have had a CNA suffix rather than the DZ letters.
That may have something to do with the late, 1970-1/2 model year introduction of the second generation Camaros where the Z-28 had a high performance 350 engine instead of the "special" 302.