For 1970 Mach 1 with 351C 4V WITH A/C and P/S, what is the correct water pump pulley? C90E-8509-F or C90E-8509-G. I have the -G, It appears to be 1 inch larger in diameter than the -F.
All I have for reference for 70 would be the MPC from May 75 so it will only list what Ford said would fit and they had available in that year
Or possibly (if the part was still available) what was the original pulley
With that said it shows for 351 w/PS
C9OE-G with an outer dia of 6 61/64" and with one sheave
Also shows a D1 replacement but that would not be of interest for you
Hope this helps in some way