1966 L72 Biscayne

[fsc66]

This is all I can say based on the following. If the trim tag is original, we know that a Group 2 code Q means the car came with an M21. We also know based on the previous posts that the only engine for the 66 Full Size Car including an M21 was the L72. If in fact the Trans is original to the car that further substantiates the L72 once again. I would be curious if the Tach harness was up under the dash as the car would have had to have a tach.
Records show a combination of model 15411 and 15611 total of 225 L72's between the 2 DR Biscayne and 2 Dr Belair.
Paul