It is an automatic car converted to a 4-speed. It was parked in the Class of 1973 display, with my SD455 Formula at the MCACN in 2013. Very nice car. One of 180 autos produced out of 252 total SD455 Trans Ams. There were also 43 SD455 Formulas built.
(You could not get A/C with a 4-speed on an SD455. Many people tried to order them that way and the orders were kicked back with the instructions to the dealers to either drop the A/C or change the order to an automatic. Many potential buyers had their orders cancelled due to the ordering snafu when the dealers neglected to recontact the buyers about the problem. Since all the SD455s were built in the last month or two of production, there was a very small window to fix your order before it got cancelled outright and you had to try to reorder the car as a 1974.)
Here it is at MCACN:
