'70 Yenko Nova 4-speed trans'

[YENKO DEUCE REGISTRY]

In regard to '70 Yenko Nova 4 speeds:

Does anybody have any ideas as to why the '70 Yenko Nova 4-speed cars were ordered by Yenko (per his order form) with M20 wide ratio Muncie transmissions, plus, all broadcast sheets found to date have an M20 code on them, and the remaining Canadian COPO Nova's 'GM of Canada' documention sheet shows code M20, yet all cars with original transmissions have an M21 close ratio trans just like Yenko's dealer brochure specified??

The only logical suggestion so far is that the COPO #9010 changed the transmission to an M21, but if this is true it would not follow the '69 COPO examples of 'engine only' changes. There is a possibility that the practice changed for 1970. The '70 Yenkos did not receive a unique engine ID code like the '68 and '69 COPO's. GM stamped the Camaro Z28 codes of CTB=4 speed, and CTC=automatics, and the Nova VIN # into the same pad.

The second logical suggestion is that the trans change was part of COPO #9737. Most feel that this COPO was a carryover from '68 and '69 which did not specify any changes to the trans. There is also a possibility that this COPO # may also have changed a little for 1970. The Yenko Novas did not receive 15 inch rally wheels from '69, and didn't get a larger front sway bar only, (they received the F41 Suspensions which had a larger front bar, and a rear bar with special shocks which supposedly was only available on Super Sport cars). The Yenko Novas also received a Big Block trans crossmember, a change to COPO #9737 or part of carryover??

Any insight or thoughts are welcome!!

Marlin