Hot Rods 1940-1948 rear ends

Sometime ago I read in Street Rodder how to determine the year and gear ratio of a Ford rear end. I have a 1932 Ford roadster that it has what I think to be a '41 Ford rear end in it. I think the ratio is 411. I need to know exactly what I have but can't remember what issue I read it in. Any help????

 

I think they are stamped from the factory on the center section webbing underside it should be stamped 9-37 for a 4.11 ratio

 

check the "bug" where the speedo cable connects to the torque tube. It will either have 2 nunbers...ring and pinion count or one number like 19 or 21. That is the code for the gears that it came from the factory with. The stamped numbers under the housing may need some wire brushing to see them.

 

Just looked at the 2 rears i have and the bug on the 411 rear reads 21 and the 378 rear reads 19

 

Thanks to all......I'll check that.