['ol Pinion head]

the 7043273 is its own case, Rochestor Products def kept building the 7043273's, & these were avail until depleted and one started seeing the 17054910's like you could order at a dealer & Nunzi used to offer in his catalogs in the late 70's & 1980.

On another front, I've never ever heard of a Service Replacement dated 7041273. Have several dates written down when originals were made, with the last one, the date one will occasionally run across on a late build 4 speed '71 T/A (F body plants had them for RA Formulas & were using them up). So few RA 4spd A-bodys were built at end of the 71 model year, remaining plant inventory of original 1273's was sent to Service Parts. Add to these, originals sent back to Rochestor for factory reman & there was a good supply in the factory parts system. Eventually these were depleted, & at the dealer one had to purchase a SR dated 7041270 (usually 74 dates). This 71 all HO service carb was eventually superseded by a 170# Service replacement, forget it off top of my head.

On original 7029273 's, have had my hands on half a dozen, & viewed quite a few more originals bolted on original & restored cars. Have never seen a SR dated one, always the 7029270 service replacements. Used to avoid those like the plague. Very odd!