I went to my stash to do some comparisons again. First, some folks confuse the TRW pumps as federals. The real TRW used up to 68 did have pulleys about the same small dia size. The BB versions push the pulley away from the pump as I stated early. The same for the Federal pump. SB hug the pump, BB are further out. The Federal BB pulley is 2951128 3 spoke. This was the 1969 A body 383 and also the big block C body. I did see some solid Fed BB pulleys, but I believe the were for later years and C body. Here is a picture of the Federal 2951128. It will look like the saginaw 2951203 just no key way.

The saginaw pump would have been the B and E body pump in 70-71 except for the Hemi and Trans am cars which used the federal.