Thanks for all of the responses! What is the reason the flywheel cover will not work? Is it something I could grind /drill to make it work or are there major differences?

no. the 2 mounting tabs on rear of cover where engine attaches to inside of transom unit are closer together than later model mounts. UNLESS you use the orig inside part and attach new(er) outer to it. the 8 bolts that go through transom to clamp outer to inner are in same place.

+1 just reuse your inner transom plate and all will be good. also make sure when reinstalling your motor you got your fiber and spring washers on your rear mounts. very important.

What is the boat?

Are you also doing engine work, or only the outdrive upgrade?

Thanks for all of the help! Unfortunately I cant complete doing the gimbal housing swap. I found out my transom is rotted Goodby boat Thanks again everyone for all the help

Now that you have stoppped wringing your hands with the towel... are you so sure you want to throw it in?

A rotted transom is not always a kiss of death.

Having said that, chances are if the transom has a problem, so do the stringers and any bulkheads which might be in the general bilge area.

If only the transom, an effective repair is a ceramic mix which is poured in. Not cheap, but works very well and is relatively easy.

It is a 1977 boat and probably if the transom was only rotted I would probably repair it. But the floors are spongy in certain spots which probably means the bilge area inst in the best condition ether. Do you have the link to that ceramic repair you were talking about? I would like to save it in case I need it down the road. I never knew that had such thing. At least now I could also get a v8 in my next boat. You cant beat the sound of a v8 haha. Thanks again for all the help