I have a RS SS 396/325 with a turbo 400. I found a plate on the pass. side of the case.

TURBO HYDRAMATIC
BC 426

CC-G8 17872

It is hard to read so I am not sure I got the numbers and letter correct. The car was built in the Van Nuys plant and everything else seems to line up and match. It is a 03D build with a T0227MY with VIN stamped on the deck of the engine.

CC is the code for a transmission used in an L35. G is probably a 6 and combined with the 8 indicates the model year 68. The last 5 digits are probably an assembly number (like a part number), or possibly a sequential build number. 426 is an assembly date, 426 days from 1/1/67 so this would correspond to the 81st day of 1968. Roughly March 20th or 21st.

Mark ,
The car is an 03D build and an L35 so it looks like the original trans..I could not find a VIN or a date that made sense to me.

Thanks !