As none of the published Pontiac wheel code charts seem to be completely accurate, why not create a chart of our own?

I'll contribute two right now.
JA 14 x 6 Rally II 4.75" bolt center 4.25" backspace 2" center bore
JC 14 x 6 Rally II 4.75" bolt center 4.00" backspace 2" center bore

If you're not familiar with the terms, the methods to measure can be found here: https://www.rsracing.com/tech-wheel.html