Thread: 402 BBC buildup - combos???

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I did it. It's not that hard if you know what you're doing. 425 horse should be cake.

Originally Posted by 69elko

I did it. It's not that hard if you know what you're doing. 425 horse should be cake.

I agree.....Im just saying it's easier if you can start bigger. And how do you know the valves wont clear? We dont know for sure what pistons are in there, and it shouldn't be an issue if he doesnt get crazy with the cam.

Originally Posted by 1JohnnyO

I agree.....Im just saying it's easier if you can start bigger. And how do you know the valves wont clear? We dont know for sure what pistons are in there, and it shouldn't be an issue if he doesnt get crazy with the cam.

Well, I've already been through all this before with my 396. I had a set of 2.25 valve rectangle port heads on my 396 with KB pistons with a 250 duration isky cam. I clayed the pistons to check clearance and there was none. The valves don't fit in the valve reliefs. I switched to a comp magnum 230 dur. with a 520 lift just to see where I was at and I only had .060 clearance. Which is bear minimum. So I went with different heads. KB, TRW, and Silvolite are the only manufacterers that make pistons for a 396. None of them are machined for 2.25 valves, 2.19 is the max. size valve.