Technical Flathead 3 Speed Case Differences

I have the opportunity to trade some backing plates for a 3 speed flathead trans from a truck. Its a late 40's synchro trans. I was wondering how much bigger are the cases from the popular 39 trans? Will it be a drastic difference fitting it in a Model A behind an 8BA?

 

If I remember correctly, only the heavy duty 4 speed is larger ( you really dont want it ) it may be an open drive 3 speed . If a torque tube set up it should be the same size .

 

The light duty 3 speed transmissions from 1942-52 (toploader type) use essentially the same gearbox casting as the 1939 box. There can be some subtle differences in the gears but the main difference is the open drive mainshaft and the open drive type rear bearing retainer/rear support casting.

if you’re not sure what you have, just post a picture of the transmission and someone here will confirm it.

 

Thanks very much I’ll post one right now.

 

Here’s a shot of the trans

 

Yup, a standard F-1 transmission. Great for use in hot rods. Can easily be converted to closed drive with some 39-48 passenger car guts.

 

Thank you very much. I’ll grab it, was just concerned it would be huge in the sedan. Appreciate the input!!

 

If you do convert to closed drive, the open drive hardware has value, but you already knew that.

 

This is from the transmission man himself website
Go over and check his site out . He’s put a lot of work to create . parts list also