I know there has been a couple of simular threads about small blocks, but they were looking for 550hp and I know some people on here had a lot of ideas concerning Small Block power, like JcPerf, and others.........

What would be the best combo to make a reliable power in the 425 to 470hp range out of a Small Block???

Thanks in advance!!!

Chevy High Performance magazine built a 383 SBC similar to the ZZ383 (425 HP) crate engine, which will work great in a marine application by the way, mounted a centrifugal supercharger and pulled just over 500 HP on the dyno.

Which month was that in??

I would go with an aftermarket block and around a 3.875" stroke crank which will give you around 417 to 421 CID depending on bore you go with. Get a good 215CC 23 degree head and a sinlge plane intake with a mild cam you could achieve your goal and not work the engine at all.

Can you swap out for a big block? Could be a lot cheaper.

Well, not really.....The boat is already set up for twin small blocks. Its a 28ft Boat so we are trying to keep it as balanced as possible. I'm afraid that twin big blocks would be too much weight in the rear.

dart little m 434 sounds nice

I just built a 410ci small chevy, 4.040 bore X 4.00 stroke using my late model "880" cast# block.
It Dynoed at 492hp @5400, 521tq @ 4500 N/A.
Reliable? We'll see, but it sure runs strong.

406 SBC -- mo-town 220 heads, spiral loc o-ring fel pro head gaskets, cam: 236/242 dur. 555/548 lift 113 lobe centers roller cam, 1.6 int 1.5 ex roller rockers, performer RPM air gap manifold, 750 mighty marine demon. 800 rpm idle, -- 521 ft/lbs @ 4600, 496 hp @ 5700. -- 125hp nitrous shot occasionally to 7K. Volvo SX outdrive. -- Two seasons, no problems.

The engine build-up was over several months. It was one of the best build series I've read.
You can go to Chevy High Performance's web site and read all their past tech articles. They have a wealth of info for anyone to print.