There were NO muncie transmissions of any type built in 1974. Production ended in 1973 and the transmissions were saved for Vette's, Z28's and TransAms. Switch to Borg Warner was stated in a GM letter in Jan 74, however there were Muncie's left over and used up till late Feb or early March 1974. My original 74 Z28 02B came with M20 muncie. Something I noticed from your photo stamping has the vin and date code stamped together on one side of the transmission, mine has vin one side and date code on other side. And whats with the xxxxxxx, never saw that. Your transmission is a re-stamp...and a bad one at that.