I recently bought a project car 1975 TR7 heavily modified with small block and what was supposed to be an M22 trans. After taking pics of trans and decoding I found out it's a 1974 M21. Research is confusing at least. Date code P4R23B. 1974 M21 October 23rd? Serial vin 14N192910. Late Camaro production with M21 ? Other #'s coincide with 1970-74 M21, case #, side cover,and tailshaft. Could this be the last camaro produced with the M21 ?