The NPD core for NON A/C (my car) is 2" thick. The part number you referenced is for A/C. I had already called NPD earlier today but greatly appreciate your help here. I've also called Classic, PY, and Ames. Classic had "notes" that indicate that the Cramo and Firebird cores are NOT interchangeable. PY had no cores in stock to measure. Ames (which is in the middle of a change in ownership and very hard to get a hold of) has one that is 2.25" thick.
I'm thinking of buying a BBC Camaro core and having my tanks put on it.
