You can use the car 4 spd. Saggy box; just don't do burn-outs, side-step the clutch or get heavy with the throttle...........they die easily. I know, I have killed several of these when I had a car..........Man, it was fun though
Watch for the grooves in the input shaft, the tell you what gear ratios are inside.
I have a list here, but I am too lazy to type it in (hardcopy only).
How many grooves on yours, or do you have one yet?