piston to wall measurement

I don't believe that KB is telling you to double their measurement as mentioned above. If you were to do the same with the Icon forged you'd be at 10-15 thou of clearance.

That said, KB believes they can be run tight in the bore. Not sure I'd agree with that. Mine is a race only with KB's & it's going to be 5-6 thou after it comes back from the shop for a re-hone. I'm not sure it's correct but I'd rather a little loose then to lock a piston in the bore. I'd try to get with the machinist as they've probably done plenty of chevys with these type of pistons. I'd like to know how the pros set these up.