mic reading 4.337 ring end gap at .047

[DanielRobert]

Hi all,
I'm trying to figure out what shape my used 440 block(1975)is in. The pistons I got with it(out of the motor) aren't stamped anything so I assume they're stock. I took off the top ring and pushed it down in the cylinder about 2" and the ring end gap is a whopping .047!  I mic'd the bore and it's showing 4.337. Does this add up? Would worn rings create a large end gap or has my block been bored at some point in life?

[BSB67]

Measure the piston across the skirt.  Post some pics too.

If your bore measurement is correct, it looks like maybe 0.015" over.  Maybe back in the day that was a thing but not common today.

[69wannabe]

That seem's very excessive to me, some rings like a little more clearance like the keith black's but I was thinking maybe like .018 to .020. It's been awhile since I had to file fit any rings and the last one's were on a 318 with the keith black piston's and ring's and I think the top ring recommended .020 or .025 for a ring gap. I thought that was kinda excessive but that's what the instructions said so that's what it got. It ran out good so I guess that was the way it was supposed to be.....

[DanielRobert]

I'll take pics and post

[John_Kunkel]

Is this a used block? Where in the bore was the diameter measurement taken? New ring or used?

Sounds like you have a block with .017" wear. And yes, an oversize bore will open the ring gap....worn rings will add to the gap.

[BSB67]

Sounds like you have a block with .017" wear.

John, is that even plausible?

With that much wear, that would be a +0.070"

[DanielRobert]

The ring was squared with the piston down about 2".......used block and worn rings. I guess thats my question....can the rings wear say. .017 or so?

[DanielRobert]

hopefully this is a pic