Sorry to highjack but how much performance increase can be found with a drag cam?
I really dont know what i have in mine exept its a roller and most likely a nascar grind.

Read post again. Compression had nothing to do with the exhaust valve breaking. The pistons were original NASCAR. One got trashed by the valve. He had new domes built for it. Sold car before assembling engine. I bought assembled and saw no increase in power. Mph is power. Others like Eatman, Arrigtin, EEI did not find power with domes.

I would say it is easy to see why. That is a big knot in a tiny chamber, plus increased valve shrouding. Seldom do big honking domes make enough extra power to offset the amount they disrupt the flame front in chamber

So why does a w8 engine with big compression make power? Is it because the chamber is bigger? They are almost the same animal as a P7 engine.

I totally misread your post Leon, it makes sense now after reading both of your posts.

A friend of mine work at Felix Sabats shop when nascar came in and said lower the compression to 12-1 from 14-1 when it was all said in done he said they maybe lost 20hp I'm not so sure your going to see a 80hp increase just by the Pistons best of luck with it

Drag race W8 combos ran larger than 4.2 bore where you are 4.182". P7 valve angles are also different. The whole shape and design of a W8 drag race head is different.


I truly hope I am wrong. Hope you have the ticket. Just know my experience. Could have sold you 8 pistons. One you could test your welding talents on. Keeper scuffed it just a little LOL

That billet would weld up just fine. It's the cast aluminum and pot metals that are a MF'er to put a decent bead on.

I'd take a look at it if you wanted it fixed.

I don't plan to put them back. They made less lower. I might would weld the original billet flat top and put that set in. But, no.

Theses pistons have to much piston to wall clearance for drag race. New set is just too cheap. Then I can get a better for application ring pack to.