You have to change the gimbal housing to match the "new"engine. The mounts on
your engine are different.

I'm not sure I understand what you are calling the "gimbal housing". The
gimbal bracket is mounted to the front of the engine and rests on one of the
stringers. Are you saying I need to change the gimbal mounts to the stringer?

Why change the engine, have it rebuild? It is les money and you get a one
year warranty.

This block is severly cracked, its cracked the entire length of the block on
top and a 15" crack between the freeze plugs. Its toast.

Mercury told me there is also a difference in the flywheel and the rear coupler
on the different year motors. I guess they just didnt want to take the time to
tell me what year engines COULD fit. They did say they only used this motor 2
years but couldnt even tell me which 2 years. I know what one year was!