454's were built for automobiles, but can be built to handle higher rpm's to make them safe for high rpm's that we run them in. anyone can put a motorhome 454 in a jet boat, and it will run fine. by changing the motor internals (cam, lifters, rockers, manifold, carbs, fuel systems, ect...) will make it a much more stout motor. these upgrades will usually keep the motor happy and give you years of run time on the river.Looking to pick up a 454 for my Sleekcraft. Kinda new to the boats scene. Is there a difference between a car motor and a marine motor? What are the differences? Thanks for any help.