Hello all, my name is Eric I live in Phoenix and I'm having trouble picking out some new heads, cam, intake manifold and the like for my baja rebuild. (complete, EVERY screw removed type of rebuild, also my first boat rebuild) It's a late 80's force, the engine is not any newer than early 90's. Anyway its a 454 mag with the 3 belts, old school. I just ripped it apart today and found that its not stock, 1.7 hydro rollers and high compression pistons are what I've found so far, heads are stock. Don't know about the cam yet going to have to wait till that comes out, but no matter its pretty warn and will be replaced anyway. My mechanic tells me not to bother with FI just go with the n/a setup, its a bravo 1 (not XR, X, XZ, or anything funny). I'm looking for a head/cam package to take this thing to the next level, I want all the ponies I can get out of it and its in a million pieces so the time is now for an upgrade. I figured I would stay with the dual plane manifold, its a big boat (28ft), and some kind of holly 4 barrel. I'm also open to the idea of new pistons, but don't want to if I don't need to. Pump gas would definitely be preferable. I also ain't got all week, any suggestions on packages would be gold, but I know prepacked solutions aren't always what they are supposed to be. I just want the most efficient setup without rebuilding every season, a.k.a "my dream motor". Any Ideas or notes of experience would greatly be appreciated. Also any suggestions on drive modifications would be great although I hear its not really worth worrying about. I need some opinions!

Call Bob Madara @ Marine Kinetics. He's the one and only in terms of cams. He can then advise you on what will go with it. Stay away from the "packages" All applications are different, build it for it's intended use. It will cost you about the same as if you went with an off the shelf deal. Dp it right, do it once.

Welcome to OSO

Welcome to OSO. You are going to love this forum has more info than you can image you came to the right place thats for sure.

domed pistons? you now have 8 ashtrays. flat pistons with 113cc open chambers gives you 9:1 comp. i am surprised those hi comp pistons aren't burnt up. stock heads; rect ports? not little round ones like in my hatteras?

+1 for bob,,and learn to ignore some other posts on here...

you mentioned high compression pistons. look at the part numbers on the tops or sides of the pistons and google them. will tell you the maker and dome size. then check your combustion chamber volume minus the dome volume plus the head gasket volume and compute your compression ratio. 9:1 is best for pump gas with iron heads. you don't want any higher especially with a fairly big boat with one engine.

Hm, I wonder if the OP is still in this thread?

yep,i know what you mean

His heads shouldnt be 113cc. They should be 118-119. A flattop in a 4.250 stock 454 Bore with a single valve relief in the piston, and stock GM mag heads, it will be around 8.2:1 give or take.

Most people assume a flat top piston nets a certain compression in all big blocks. Small bore 454 based engines need a little dome, or a smaller chamber to get to 9:1 neighborhood. And 114CC chambers with a flattop wont do it. More like 102-104CC chambers.

Now, the above combo in a 4.500 bore, yes, you have a 9:1 engine with 118-119CC heads and flat tops.

[QUOTE=A.O. Razor;3641658]Call Bob Madara @ Marine Kinetics. He's the one and only in terms of cams. QUOTE]