New to the site just bought a 71 Cutlass with a 69 455 motor that needs some work. I'm Trying to find out the proper end gap for the rings on a 69 455 that's bored 030 over. Any info is appreciated.
Thanks
Justbill

 

Welcome. For stock-style cast rings, factory spec is 0.013"-0.023" for the two compression rings and 0.015"-.0.55" for the oil ring.

 

As a general rule of thumb, you can use .005 for every inch of bore and that will put you in the ballpark for ring end gap. The Hypereutetectic pistons generally call for .0065 per inch of bore for the top ring only.

If you think these are excessive, check the factory gaps on what came out of your engine.


BTW I'm talking only about the compression rings. I've never had a problem with gap on oil rings.

 

Uh, the factory gap specs I posted above match up exactly with your 0.005/inch of bore.

4.125 x 0.005 = 0.021" gap. Factory spec is 0.013-0.023.

 

Joe. Where in N. Virginia are you located. I'm in W. Springfield.

 

Lovettsville in Loudoun Co.