Re: Engine swap
Allot depends on what your boat currently has in it right now for an engine (year,model,), along with the specifications of the crate motor.
If your boat has a 1986 or newer engine, chances are the engine in your boat has a 1 piece rear main seal, where as the crate engine most likely has a 2 piece rear main seal. The difference in rear main seals will dictate whether or not the flywheel will swap between engines.
There can be a difference in cylinder head design as well. The 1982 crate engine could have cylinder heads which are either high compression, and/or intended for high RPM use, where as most marine engines like the one installed in your boat primarily used truck style heads which are low compression, and intended to build power at lower RPM's (what a boat needs). The other issue with heads is ensuring your intake manifold will bolt to the '82 heads. There was 3 different design changes to the gen 1 intake manifold bolt patterns over the course of the small blocks history. The '82 will have the original design with 12 bolts at the same angle. The newer heads ('87-'95?) with center-bolt valve covers will have 12 bolts with the middle 4 bolts at closer to a 90? angle than the outer bolts. A manifold for Vortec heads will have 8 bolts, and will not work on older engines.
The cam shaft in the crate motor is most likely not going to play nice in a marine environment, so it would need to be swapped out with a marine spec cam.
The core plugs in the crate engine are most likely steel, and should be swapped to brass unless your boat uses closed cooling.
The cylinder head gasket is most likely plain steel, or steel cored, and should be changed to a marine grade gasket (steel gaskets can rust through especially if used in salt water).
There could be more differences, so again it really all depends on what engine is currently in the boat.
