they did put rochester 4 barrels on boats and they are good carbs if you have one they are easy to tell the boat carb has no taps for vacuum and the base plate is black in color.they work good but tune up parts are hard to find .but if it works use it . on the intake it woud use a dual plane or air gap ,i do not know how much cam or how much cr you have so the intake is a good guess i use to run themo quad on my old 396 with dual plane and work geat .you can spend a lot of money but it mite not run any better. make sure you have a good exhaust.you cant get it in. if you cant get it out