Maybe I'm confused on what you mean by "gapping"
To me, gapping is the process of filing the piston rings down, so the ends do not contact each other in the hot motor.
I did not gap my rings, I merely checked the oem parts to see if there was an adequate gap between the ends of the ring inside the cylinder.
I recently put new piston rings in along with LS pistons, and I did not gap them, as I used OEM parts. Haynes manual says it must be done on non-oem parts, but I followed the procedure, which states:
put the ring into the cylinder and push it down, so it compresses together. Then measure the gap of the rings inside the cylinder. If it's within tolerance, no gapping is necessary.
As for me, no gapping was necessary. And, now it runs perfect,
that is except for my misfiring problem