'70 Yenko Nova 4-speed trans'

[JoeC]

Marlin, According to some of the Camaro books (and CRG web site) the M20 was used as a generic term to denote a 4sp trans. on some of the paperwork. The paperwork would use the M20 code for the Saginaw 4sp and for the Muncies but the letter code on the build sheet should be for the correct trans. (I have original paperwork on a 1969 307 Camaro that has the M20 code but the car came with the cast iron Saginaw.)

I'm not sure what you mean by 69 COPO "engine only" changes. The 1969 COPO codes came with a long parts list in addition to the engine. The 9560, 9561, and 9562 COPO order listed special rear end parts, springs, radiator, hood, tires, etc. The 9737 code listed more spring options, speedometer parts, wheels, tires, etc.