Somewhere in the Mercruiser forum I read that the 4.3 out of an Astro van with do the job if you switch everything from your marine engine onto the truck block. The big deal seems to be that marine engines need hardened cranks journals etc. so they can run WOT all day . Its my understanding that the truck versions have the hardening to deal with the towing chores.
Do a search there and it should pop right out.
This should run through what years are interchangeable. you may want to consider getting a newer vortec long block either as a reman complete base engine or from a truck at a wrecking yard
thought I would post the complete history of the 4.3 liter that I could find. These are links and articles that I have bookmarked for my own use, however they should help many people. it may help some people when looking for parts or sourcing a salvage yard motor or a reman. keep in mind that...
forums.iboats.com
