with a taper drill, the tip of the screw is doing the bulk of the pulling as well as absorbing the most torque. SB is not strong enough. bore the hole deeper or just use a straight drill. In fresh water use ss screws.

The Crown is 2 inches longer that the Ace. The coupling and rear bolt holes should line up if the transmission is the same ratio. The front mounting holes will be several inches forward of the Ace holes,
Bo