in between version; pull heads, remove all valve springs and free up and clean up all valve stems-guides. relap seats. take a cheapie 3-stone hone and clean up each bore as best you can with each piston all the way down. check the underside of the water passage across front of intake since you have it off.

safest risk would be to pull heads and clean/inspect, rust and junk could wipeout cylinder. check lifters also.

Also if a valve sticks for just a split second the piston will hit it and you will have more issues then you want.

Thank you all soo much, I will start wrenching and see how far I get.

first and quikest would be valve covers then turn motor and look for valve staying open. if 1 is sticking, pull heads and free up all 16. the other 15 sat just as long in same environment...

Thankyou all, to follow up. I ended up putting atf and pb blaster in the cylinders, hand turned the crank a few times every other day for a week. It freed up and on a fully charged battery it started.

and?

And I hope to get out on the lake tomorrow, its been over 2 years without a boat.

you are probably ok.