"Is the block stamped HP like 68-70?" Yep, on the pad by the distributor it's stamped 383 and then below it's stamped HP. the build date is Nov 70. In just thought if someone has the car and is looking for it, it's available.1=Model year 1971. There is only a 383-4bbl or 383-2bbl for MY 1971. There isn't a 335 horse 383 like 68-70 nor is there really such a things as an HP block. Is the block stamped HP like 68-70?
B= Hamtramck plant = A and E bodies. Meaning it's out of a Challenger or Barracuda/Cuda. Someone with a better 71 Hamtramck database than I can help.