I have two engines. A gen 5 and a gen 6 bbc454 . Was wondering which one is best to build for my 1970 bubble deck. Both engines have bout 120k miles on them and are not marine but run great. Could I Marinize and use for a while without new pistons n crank. I realize the cranks are not forged steal but thought I could possibly bolt on marine equipment and go a few years before balancing and blueprinting the whole engine. Appreciate any help. This will be a project jet boat