Tigershark3

What is the significance of the first digit 2 in before the RPO# and the two letters after the RPO#.

Example: 2M20AA is a 4 speed Muncie Transmission

Thanks in advance
Greg

Powershift

Can't help with the "2" prefix. But the "AA" suffix is the exception code that provides additional detail on which cars can accept this option. AA should be all cars.....no exceptions An AB (for instance) might be the option/part is for only a big block car, or something similar.

An actual/better example is Option N14 side pipes, AA indicates it fits small block car, AB means it fits big block cars, AC is for base engine and automatic trans, and AD is for BB engine with auto trans. Get the idea??

Larry

EDIT: Most of the guys doing reproduction window and tank stickers know all about these suffix codes. But years ago, that was not the case..........and it provided a way to tell if a document/sticker was original or a reproduction. A lot of early reproduction tank stickers missed this for the big block side pipe cars and coded all with "AA" suffix.

Nowhere Man

AO Smith used more letters then St Louis for there billing purposes to GM

Powershift

I have both an AOS small block car and the factory tank sticker.

Larry

Tigershark3

Can anyone comment further on the "2" prefix?

Greg

JohnZ

Simply an accounting classification code signifying Corvette usage.