Need opinion from those that KNOW.

That is a casting number. The Chrysler part number for it is 03461184 I Did a search at Rock Auto. More Information for RAYBESTOS MC36308
Buyer's Guide : RAYBESTOS MC36308 Master Cylinder
DODGECHARGER1971-1972
DODGECORONET1971-1972
DODGEDART1971-1972
PLYMOUTHBARRACUDA1971-1972
PLYMOUTHCUDA1971-1972
PLYMOUTHDUSTER1971-1972
PLYMOUTHGTX1971
PLYMOUTHSATELLITE1971-1972
PLYMOUTHSCAMP1971-1972
PLYMOUTHVALIANT1971-1972
Ignore my Canadian pricing. lol