I can quote you the numbers from the 1964 "Parts and Accessories Catalog" but, be aware that earlier numbers may exist and be superseded by the ones listed in this catalog.
* 38-53 216 forged 838733 p/n 3836491
* 41-53 235 except PG 3736023 P/N 3836490
* 53-55 corvette, 54-55 utility(1st series)261, 56-57 series 3, 58 series 3 except D-D,58 D-D (1 st design), 62-63 all 261
3836390 P/N 3836484
* 54-55 all 6 cyl except PG, 58 D-D 2 nd design,59 series 3, 60-62 series 10-30,60-61 fleetmaster exc. PG,63 4WD 1st series.
3836127 P/N 3836482
*54-55 passenger W/PG, 56-58 passenger.
3836386 P/N 3836483
*58 taxi, 59-62 passenger exc. fleetmaster, 60-61 fleetmaster w/PG .
3752736 P/N 3752735
Heaven only knows what the difference in some of these were, but GM thought enough of the need for a difference to spend money to change them.
Last edited by enginenut; 05/08/2012 1:56 AM.