If you are using the cooler fittings in the GEN VI block, I believe Scoggin Dickey Chevrolet (SDPC) has the parts and info to do so. There are many articles here on OSO of what needs to be done with the oil filter pad adapters and the bypass's on the oil filter pad.

Have to check that, thanks.

Measured piston ring end gaps, top ring=0.01771", lower ring=0.01574". Seems very tight, these are Hastings stock replacement rings for mercruiser 502.

This part is mandetory if connecting an external oil cooler to a Gen VI big block Chevy 427, 454, 502 engine to the factory oil cooler ports on the oil pan rail of the block. Without this part, the oil cooler will not be functional. This part is designed like the factory quick connect design so that it blocks off the upper oil gallery that the oil cooler port intersects.

This part threads into the port on the oil pan rail closest to the oil filter.
This fitting is the pressure supply to the oil cooler.

The return line (port farthest forward) can be a standard 3/8" NPT to 10AN adapter fitting.

on the bypass's,,I'd block the the one in the pad and remove the one in the center inlet to the engine.

0.020 - 0.023 in a stock application.........measure them about 1 inch down in the bore

what type of measuring equipment are you using to get a five digit measurement?

block #3,remove the bypass valve from 4 and use 1 and 2 for oil pressure sender and oil temp.

Should i use oil filter without relief valve or with relief valve? (filter installed in the filter pad of the block). with sd1540 fitting my oil lines are limited to AN10 fittings, but i think this is fine for max 500hp engine. it would be nice to hear some oil cooler suggestions also. Really appreciate your help!!!