4 Speed Identification?

Hello, I have a connection that has few manual transmissions for sale. What are the identifying casting numbers or other characteristics I should be looking for in a 4 speed manual transmission? My contact may also have other manual transmission parts available including the clutch and brake pedal assembly? What numbers do I look for on these? Currently I have a 1971 Challenger 340 with a 727 automatic.

Thanks for your help,

Tirekickertoo