Ford rear ends

Can someone tell me how to determine what year and gear ratio a rear end is? I have a '32 Ford roadster but am unsure of what the rear end is. I read something about it in Street Rodder but don't remember which issue. Some help please

 

Not too sure if ford did this in 32 but I know on the banjo rears there were two numbers stamped into the casing. Take one number and divide it by the other and that was the stock ratio. Thats not to say if the gear was ever changed. Or you could lock one axle and spin the pinion while counting the number of revolutions it takes to make the axle go around once.

Mike

 

A picture or 3 would be a great help in the ID dept!

I ***ume open driveshaft and non-Posi.
To allow for the differential action inside the rearend you do it this way...

Block your front wheels and have the car on a level surface.
Jack up one rear wheel, use an axle stand and leave the other tire on the ground.
Mark the top of the tire with some chalk or something.
Mark the pinion yoke and the housing right next to it.
Rotate the tire 2 full exact turns while counting the revolutions of the driveshaft yoke.
(this allows for the 2-1 ratio of the spider gears/side gears inside the diff)

3 & 1/2 turns of the driveshaft will be 3.50 to 1 ratio.
3-1/4 will be 3.25's
4 and a bit will be 4.11's
3 will be 3 to 1 and so forth.
This will get you close enough for any calculations you need or want to do. Once the Rearend is ID'ed you can decide which available ratios match your findings.
The 3.5 turns might actually be 3.55's or 4 and a bit might actually be a 4.10 instead of a 4.11....but your very close regardless.

For a Posi you need both wheels off the ground and rotate the driveshaft as many times as it takes for ONE full revolution of the tires.
No diff action to allow for.