Is it a gen 6 454 or an older one. Marine engines are high nickle castings stronger. Should also be 4 bolt mains 330 hp should be big port heads. If it is a late model it will also be a Roller Cam. Will use a little more oil on the street do to the added piston clearance set for marine applications. In my opinion not a bad deal if it is a 96 or newer and complete. The marine set up will make great torque and run good to 5200 RPM's. Has a different cam grind than the truck engine. All late engines are 4 bolt mains. The stock 502 cam would be perfect for a cam up grade if it's a 96 or newer. You can re use the lifters, need to change springs and intake gskt. other gskts are re usable if not damaged. Late model's also require electric fuel pump. Also will not be able to use dist unless it is an older engine.