kb107

I'm not a builder, but .032 does sound large. I used the KB .0065 ring factor at the first build. But in late 2000 when I opened up the bore an extra thou,(now at 4.050),I put the same rings back in, so I guess they would have been around .029. I didn't keep notes cuz I never even thought it might some day come in handy. I took that engine apart every winter, 5 winters in a row, to catch trouble before it cost me big money. I figured gaskets were cheap compared to what I had in the engine. And sure enough, the first three winters I caught stuff. By the 4th time,she was A-OK,
But I took it apart one more time in 2004, and installed Plasma-Moly file fits, back at .026. Man I couldn't hardly see any LeakDown on the gauge. But it ran and it was dynomite.The one and only successful trip down the track (of 4), it posted 93MPH @3467 pounds(1/8th). I was ecstatic. The engine has not been apart since.

I don't know anything about chebbys,lol, but hypers at .004 in a streeter, I agree sounds like a lot. My whole reason for choosing the hypers in the first place was to run a tight skirt clearance. I mean the catalog said .0015 to .002 for street, up to 4.1 bore, so plunked my money down.
A long time later, I got to thinking about why the skirts had not scuffed, and I confess, the thought came to me that perhaps the skirts hadn't locked up at all, and it was the rings butted up. I never did go looking for the evidence. And the file-fits went in at .026 and the lock-up issue never returned, so I put it out of my mind.