I have a Mercruiser 350 chevy engine and a 1989 Ski Nautique with a blown engine.  Does anyone have any conversion parts or source to marry the 350 with the 351 Windsor transmission?  Thanks!

There are plenty of them out there new or used, (same mounting bolt pattern as a Borg Warner 71c,) but........you need to know what this Mercruiser engine has for a flywheel. It'll be either 168 teeth (14 inch diameter) or 153 teeth (about 12 3/4 inch diameter

Your starter location also comes into play. You might have a bottom mounted front entry starter (just like the automotive location) or a top mount rear entry starter on your engine.

With that info you can come up with a bellhousing that'll work. Some of the bellhousings will work with either starter and some only work with one style or the other.

It won't matter if the bellhousing is from a Mercruiser 350 inboard, A PCM Chevy, an Indmar Chevy or a handful of other brands as long as it will adapt the engine to an inboard style transmission

You'll also need a damper plate to bolt to the flywheel, but the good news is that the one on your Ford  now for the PCM 40A transmission will also fit the Chevy flywheel. There are multiple mounting holes that can be used. 

If yours isn't in good shape, now would be the time to replace it. The only way to get one for the 40A is thru PCM and it gets kinda pricey.