The marine 350’s are built quite a bit different than the regular automotive engines. I used to work on both. An 80’s 350 (if its out of a light duty van) just isn’t going to produce the power, or hold up as long as you want. That will be a low compression ratio, 2 bolt main block, with EGR and A.I.R. cylinder heads. You could buy a long block 350 marine engine and come out ahead in the long run.
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