How much ring end gap for a 4.47 bore,naturaly asspirated.I run closed cooling so there is less extreme cooling shock.

I used the ring manufacturers recomended then add
.002.


Mine are at .008 4.530 bore.
Supercharged 8 lbs boost.

NA closed cooling?
Run std Mercruiser spec for hp500.


caveman, that sounds awful tight for a SC motor.

No less than .0045" per inch of bore. And then add .002 for the top ring like caveman said. Err on the big side, too big a gap wont hurt you, too little will.

Yes I would say so

Sorry guys I missed the 2

.028

HARRISONMIRAGE,
What piston/ring package are you using?
Bob

Cave,

much better.

It is stock GM.I boaught a zz 502 that I have torn down and are building for marine use.The factory ring end gap was .024 already wich I found interesting seeing as these motors are getting such a bad rap for marine use,for such issues as this.I am glad I tore it down cause the block had a casting pitt in one of the bores and had tobe repkaced.