Blair, if you go to
this page on my website you should get the information you need. Good luck.
I remember when I was doing up my 69 Camaro RS/SS 350 several years ago and the POP was all correct except the same Carb code. I think it had a "C" instead of the "R". I contacted Jerry MacNeish about it and he mentioned a number of these were that way and apparently Carter made some Rochesters.