Flywheel bolt pattern

[Nick2020]

I am replacing the engine in my boat which had a 1984 omc 5.7 with the stringer. I bought a used 1988 omc 5.0 engine but found that the bolt pattern was different for flywheel and coupler. Could I use the coupler that is on new engine, it is a lot bigger than original or could the original small coupler be modified?

 

[Bondo]

Ayuh,..... Welcome Aboard,...... Are the splines the same,..??
Will the bigger coupler clear the flywheel cover,..??

If not, you'll need to find a pre-'86 replacement motor,.....