['ol Pinion head]

Above is a term, I began to use in conversation & in text, near 25 years ago regarding restorations & preservation projects. Originally, there were no Pontiac A-body's equipped with 14x7 Rally II whels until the '72 models arrived. 14x7 Honeycombs arrived on A-body's & Formulas for the '71 model years, my HO T-37 Coupe was optioned with them, & they are also quite heavy.

If the Purpose Build for the car is to do, for instance, a PureStock build, say with a fairly easy to obtain '71 96 headed 400 engine, or restore to anything close to an as originally built 350 car, 14x6 Rally II's, coded KU 14x6's would be the way to go. Not just because its a code thing, but the wider 14x7's, as well as larger 15x7 rally II's are easily noticeable from several car lengths away.

In regards to what you are being offered, KS coded rally II's are 14x7's. HM's are '73-74-75 15x7 rally II's. The HM's are fairly much indisguishable from their replacements, the 15x7 HM's.