425...can it be built up?

[sizanjdf]

I have been researching this stuff for a while and havent had alot of luck on finding parts and such. Can I rebuild the 425 I have to make the 350hp maybe even 400 hp Im looking for? I was thinking an intake, carb, and cam kit would be great with Higher compression...10:1 approx. and bored 60 over. Id like to keep the heads and everything I have, so would domed pistons clear the heads? And does this sound like a good idea or should I get a 472 or 500, im guessing its probably going to cost about the same to build it as my 425

[STDog]

Can I rebuild the 425 I have to make the 350hp maybe even 400 hp Im looking for? I was thinking an intake, carb, and cam kit would be great with Higher compression...10:1 approx. and bored 60 over. Id like to keep the heads and everything I have, so would domed pistons clear the heads?

not sure what power you can get from a 425. But parts are harder to come by. The after market is even more limited than the 472/500 market, which is pretty small. Can the 425 go 60 over? Can you get the pistons with the correct CDs easily/cheaply? Do 472 cams work, or will they be custom grinds?

As for the domed pistons, which ones are you looking at? I'm sure you can get some made with the correct sizes and valve relief. But is it worth the effort?

I suspect the 472 would be cheaper since the parts are higher volume. More off the shelf choices.

[Modly]

The cams should be the same as any 472/500 cam, Though, you may want to use a cam a lower duration, than you would plan on using in a 472, or it will run a bit rough.

You can get any piston in a .060 over, but it may not be the wisest choice. Unless it's already been bored out, I wouldn't recommend a .060 over, just incase the block does get screwed up. I'd go for a .040 if you want the highest amount of displacement, with a block that can take a second rebuild (You sound like you want a performance engine. It will happen soon).

I don't know if anybody makes a domed piston off of the top of my head, for the 425.


Being honest, a rebuild kit will cost much more for the 425. Comparing prices between a 500 and a 425 (I didn't price out a 472 kit), the difference is about $200, and that is at jobber pricing. Most people that sell them out will have a percentage added onto jobber pricing, which could be another $50 you could pay for a 425. For performance pistons, they are readily available for a 472/500, and they don't seem to be for a 425. You might have to get them custom made if you wanted something special.

You'll get alot more power out of the bigger engines, and they can also take more.

[kevinjohnson]

400hp and 500ft/lbs are available in at least one kit that i'm aware of.

[sizanjdf]

can you show me a link to find such kits???

[acaciaavenue]

I, too, would0 like to see links to those kits or any other pertinent hardware. I'm trying to put together a build sheet for my inevitable 425 rebuild into a street motor - and I'd like to see 400hp out of it.