Quote:

I have a 4.375 stroke with a 6.535 rod in a 4.500 bore in an low deck Indy block.

By any chance do you have the skirt and piston dimensions compared to my Diamond pistons?
Specifically the total skirt length (2.555)? (that isn't exactly your problem)
And the 0.190" dimension below the piston pin?

I didn't have a problem but mine is a 4.250" stroke, 6.535" rod, in a KB low deck and I think the cylinder liner is 6.10" long ? (not measured) I wonder if it is the piston/stroke or the block...