1971 Ford 302 Low End Power Adders?

supercharger is your only option to get near that given your limitations. You more than likely do NOT have Cleveland heads as they are for high revving engines not ski boats.(like previousposter said, they are not "bolt on" either) You also probably already have a R.V./marine cam which provides the most punch out of the hole. You don't get more top w/o giving up bottom w/o going bigger in displacement. My suggestion....Play with prop size. I got just what I was looking for in an offshore go fast by going less pitch bigger cirference props. Also aluminum performed better in my case by being lighter. I gained 5 MPH w/o touching any thing mechanical. Find a shop willing to let you try-to-buy. They also make dual pitch props for out of the hole and top end speed. HP is good but not the only way to skin these cats. (BTW I hear you about not wanting to yank engines, sheesh. It's a bigger pain than a car. ) Also reverse rotation is not a big deal. cam makers grind for it. Just reverse firing order. And if you don't have twin engines, what makes you think it's reverse rotation? And why would it be unless you had changed to a left (port side) gear-box?Yes a 502 will easily get 425. But a 302? Yes 400 is very possible but you lose sooo much bottom that it really makes boat appl. tougher esp. skiing. It's why they use bigblocks so much on boats. But really, why build for HP on a ski boat? Torque is what's needed, not top speed.