I wonder as well but I think NHRA allows them on all the 63 and 64 Max Wedge and Hemi cars, plus T/A and AAR hoods on a lot of engine combos that I don't remember having them. Same thing with single four barrel hemis, I don't remember seeing any on the street or the drag strip back in the day

All I can guess is that Chrysler must have given some pretty vague documentation that is being interpreted in a way favorable to Mopar brands.

This is all fine with me as the other manufactures have done the same thing.