I'm almost sure that the ring sizes should be 1/16,1/16, and 3/16 on the oil rings. TRW, as far as I know and remember, never varied from either 5/64,5/64, 3/16 or the narrower 1/16, 1/16, 3/16 on all the Mopar Hi Po V8 pistons. I have seen and used the 1/8 oil rings on a Hi Po 427 Ford motor, maybe even some Chevy may have used them also, maybe not IHTHs