PISTON RECOMMENDATION

JERSEYJOE

CAN SOMEONE RECOMMEND AS PISTON FOR A 401 BUILD THAT WILL RESULT IN 9 OR 9.5 TO 1 WITH 58CC HEADS? ALSO HOW MUCH MORE HP AND TORQUE WILL A 401 PRODUCE RUNNING 9.5 TO 1 VS THE STOCK 8.5 TO 1 ALL OTHER THINGS BEING EQUAL. GRANTED THE 9.5 TO 1 WILL NEED PREMIUM FUEL.

ironman_gq

if I remember right a full point bump in compression will give you roughly 10 percent bump in power

kris

I was just working on this in another thread.

http://www.bulltear.com/forums/viewtopic.php?t=8673

Not a "recomendation", but the TRW/Sealedpower forged L2380F at .030" gives 9.51 with a 58cc chamber. KB also makes a hyperutectic with the same dish volume but the comp height (1.510") is higher and the rods need bushing for a smaller pin.

JERSEYJOE

Are these available anyplace?

donwag

I am pretty sure both are available. I just got the KB354 in .030 over. My machine shop got them direct from KB.

1980_Cj7

The KB's have a stepped dish design that supposedly gives better quench, and that combined with their hypereutecticness (hey, methinks I just quoined a new word) that reflects more heat is reported to let you run a little higher compression with pump gas. Unfortunately you do have to bush the wrist pins like kris said. We just build an engine with the KB's, and it wasn't a big deal though. Read up on KB's web page about DYNAMIC compression ratio. That's what you really need to be concerned with, not STATIC compression ratio, when it comes to whether the engine will run on pump gas or not. Your cam choice plays a big part in that. There are calculators on the KB site to figure that all out.