"Club Coupe" - I am doing the same thing; installing an OD transmission in my '51 club coupe. Just to make sure, do you have everything you need? Specifically, do you have the relay that mounts on the firewall? I know there are ways to "Jerry-Rig" an overdrive setup on these cars, but it kinda defeats their original purpose and leaves the setup vulnerable to damage. I made sure I had all of the components I needed before I started on installation. The lockout cable, kickdown switch, and wiring harness are all available from the after market. I had to obtain the lockout cable from a Studebaker parts supplier because none of the Ford guys had them. (It is the same as a Ford except it has a chrome handle.) Although Charlie's suggestion of the kickdown switch is doable, I believe it's always better to do things the way the factory did it on these cars. Also, the wiring harness probably won't work with the kickdown switch mounted there. Make sure the transmission came with a functional solenoid and governor.
Once you have everything and it is installed, you will find a properly working overdrive to be a valuable installation in your car. My first '51 had one, and though my current car is a much nicer one, I sure missed the overdrive.
