1955 Pontiac 3 speed

Trying to help a friend with his newly aquired 55 Poncho. Has a bad 3rd gear syncro. Don't hold out much hope of finding a part. questions:

1. will the stock bellhousing accept a Borg or Muncie 4 speed ?

2. if not, is there a bellhousing that will work on the original motor, and accept the 4 speed ?

any other info or ideas ( no auto transmissions need apply!) to make this car driveable will be appreciated, thx

 

I am going to guess it has a Selector type transmission? With one big side lever that goes in and out, as well as back/forth?

If yes, then a 4 speed won't fit to it.

As I recall reading on hamb, some 50s pontiac engine pieces fit up into the muscle car era, but I don't know about bell housings. Rocky should know.

3rd gear syncro ? grinding? or jumping out of 3rd? I may have a syncro if it is a Selector. Easy trans to work on IMO.

 

I believe that i have a good synchro because F&J gave it to me a few weeks ago for the selector tranny. You could post a thread over on the Pontiac forum as there are guys over there that have similar Ponchos.
On another note if that pontiac has a bell like the 51 + Olds you could bolt a 37-8 Buick tranny in there and have a much better shifting tranny that won't break!

 

55-60 trans bolt patterns are the same. You would need a 58-60 hard to find bellhousing for a newer 4 speed.
Another option is to either fix your light duty 5 bolt top cover or find a stronger 6 bolt top cover trans from a 56.

 

So, If that 55 is a 5 bolt, I bet an Olds 6 bolt trans might just have a bigger input shaft than Pontiac? The reason I ask, is because I had a 6 bolt closed drive that must have been a Buick, and I am pretty sure the input dhaft looked different. Seems like GM made it difficult for us to swap parts

My syncro and Vtwhead's are 51 up Olds, so I doubt they would fit a 5 bolt Pontiac.


EDIT: if you are within driving distance to NJ, you might want to contact Flatpower. His Dad had a Pontiac geared 37 Buick topshift trans with Pontiac tailhousing. Don't know if he still has it or something else that will work.

 

Had a friend in high school in the 60's that machined his 55 Pontiac bellhousing to use a Chevy three speed. The Pontiac trans was too hard to powershift. If you can machine it to use the Chevy three speed, a four speed would fit in the same place.

 

To machine it you'd have to open up that center hole, that's the big obstacle on using a later trans with one. The bottom bolt spread is too narrow, too, but you might be able to work around that.

I've wondered if you could just make an adapter plate and run a T5 out of an S10 with the long input shaft on the stock bell.

 

1963 Chevy three speed and four speeds (except 409 cars) had a smaller front bearing retainer than the other trannys from 55 on. That might make for an easier fit or less machine work.