Adding overdrive to a 1942 C-8

m_mman

Hello, I am soon to take delivery of a 42 Commodore 8 sedan. It doesn't have Overdrive but I certainly want to add it.
I am very familiar with basic Borg-Warner OD units so the wiring etc. doesn't phase me. 

But what transmission fits? 41-47 has the "Handi-shift" but is it the same mechanism-linkage as a stepdown? How far up can I go with a transmission? 

Are there any driveshaft issues. On some cars, the non-OD tail shaft is long enough that it matches an OD transmission and a complete swap is easy. Is this true for Husdon?

Are there any clutch issues between straight drive and OD?  I wouldn't think so. 
Thanks. 

allan

any single lever overdrive 41 through 51 will fit; the driveshaft will have to be shortened.

lostmind

Clutch is usually 9"  for non-overdrive , 10" with Overdrive.
I'm pretty sure 10" could be ordered as an Option.

54coupe

lostmind said:

Clutch is usually 9"  for non-overdrive , 10" with Overdrive.
I'm pretty sure 10" could be ordered as an Option.

It's an 8 cylinder car, It should have come with a 10" clutch.

lostmind

54coupe said:

lostmind said:

Clutch is usually 9"  for non-overdrive , 10" with Overdrive.
I'm pretty sure 10" could be ordered as an Option.

It's an 8 cylinder car, It should have come with a 10" clutch.

Missed the 8 cyl part. Applies to others wanting to make the change.
I'm sure there are some running around with 9" and overdrive and doing Ok ,
for now.

m_mman

Thanks. So I am guessing the 2 lever transmission started in 52?

Jon B

Then there is the question of the rearend gear ratio.  I'm guessing yours is a 4.11.  Factory overdrive-equipped Hudsons came with a lower ratio (4.50?) but when the car was an eight, it might have been 4.11.  Anyway, if you have 4.11, I would advise sticking with it because your 8-cyl. has the power to handle overdrive without pooping out on hills. I converted my '37 6-cyl. to OD 43 years ago and stuck with the 4.11, and it proved to be acceptable.

m_mman

Oh yes. An OD lowers the effective ratio by 0.7. So a 4.11 in direct (good for hills & take off) translates to a 2.87 on the highway in OD. and you would not want to go any higher than that.