In process of setting ring end gap, boosted 509"
 

so I have been reading posts on the subject and it seems the info is all over the place,
from running the ring manufacturers reccomendatiosn to running extremely huge end gaps.

I run 4.5 - 5lbs of boost ,9 to 1 comp , engine is around 650hp.
reccomended for boosted app by piston manufacturer (J&E)
is 022 for top ring and 025 for second ring
I went with 030 for top ring and 035 for second ring to give myself some leeway.
Sound about right?

I'm running .032 top/.028 2nd with gapless rings with 14 lbs of boost, the std ring's use a tighter gap normally. If I were running std rings in a 5 psi blown bbc I would use .0055 on top and .0057 x bore size, which would come out to about .025 top and about .026 second with a 4.500 bore , I might go up to .026 top and .028 second just in case you get it real lean BUT j/e recommends .005 top and .0055 second for blown street. You have to remember the blown race specs are for about 25 or 30 psi! Your numbers are mighty big, what was the reasoning for you to go so high? Procharger sells blower kits that bolt on stock 454's and 502's that don't require tearing motor down and opening up the ring gap so at only 5 psi you could almost use stock gap numbers, you want the gap as close to zero fully warmed up as possible, anything extra is just giving you more blowby / less power, Smitty

http://www.jepistons.com/PDFs/TechCo...instrc2618.pdf

hr,
That is probably a little on the big side but it shouldn't hurt anything. Better to be a little loose than too tight and have the rings butt together.

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

I had to replace pistons due to a dropped valve seat , as for ring gap, everything I read said to run wider on a marine motor and to run wider on the second ring.
Previously engine was redone by a well known local shop and the ring gaps they put in were actually bigger than what I am running. It was in the .040 range.. Then again same shop that redid my heads and then they dropped a valve seat 20 hours later. :(
If the engine stays together I may run more boost as well.
Thanks for the responses, appreciate it!!