54-56 Powerglide Help

[John L.]

I have a question regarding the idendification of a cast iron powerglide that came with my 1954 corvette. When I purchased my 1954 it did not have the correct engine and transmisison installed and was not running at the time. It had a 62 chevrolet engine and powerglide installed. Now that I am finishing up on the frame restoration, and the rebuild of my engine is progressing faster than expected, I need to focus on the transmission. Not sure if the transmission that came with the car would be functional with the correct "911" engine block that I now have out for the rebuild.

Anyways the numbers I have been able to distinquish off of the bottom of the transmission case are 3708134 GM9 L36. So I may assume since this is a cast iron PG that the date code translates to a casting date of Dec.3, 1956. is this correct? I have purchased the correct corvette tail shaft and input shaft that I need.

Before sending the block out for a rebuild I did a quick visual assessment and it seems the engine, adapter plate, and the transmission would bolt up. This was only a quick visual through. My question would be if anyone could advise on if the corrrect id of the transmission I have, if the shift pattern would be correct with the corvette shifter and any other detailed info to get me on the right track of either replacing the transmission altogether or rebuilding what I have..

Thanks to all!

[Troy P.]

Re: 54-56 Powerglide Help

I would seek out a 54 passenger car Powerglide with the correct date codes and have it rebuilt and modified with the parts you bought. In the meantime you can reinstall the tranny you have and use it. But I would not put any money into it.

To mount your longer lateer model tranny the driveshft must have been shortened and a tranny mount adapter was commonly used.

The 53-54 tranny has a vacuum modulator whereas the later versions do not. The vacuum line goes to the back port on the intake manifold.

When you get the correct tranny you will need a longer driveshaft as the correct tranny is shorter with the short output. You can have these made at any driveshaft shop.

You might look into whether or not you have the correct driveshaft yoke. The 53-54 yoke has a longer shaft. The shorter later model 16 spline yoke will still work if you don't go over any big bumps at speed.

[John L.]

Re: 54-56 Powerglide Help

Thank you Troy - I had a gut feeling that after all was said and done, attempting to reuse the transmission I have and all the accommodation necessary it would have been almost as easy to seak out a more correct transmission. so now to be on the lookout for 53-54 passenger car PG.
More to follow I am sure.
Have a happy new year!
JmL

[John L.]

Re: 54-56 Powerglide Help

Is there much of a difference between the base 1953 and 1954 powerglide units? My 54 is an early January assembly so I am assuming a 53 Powerglide assembly from October - December would be what I am looking for...
John

[Troy P.]

Re: 54-56 Powerglide Help

I think they are the same.

Suggest you call Rob Cunningham at Automotive Inc. and see if he can fix you up with a 53 tranny and do the conversion for you. He did this for me last year for a 53 I was working on. 800-926-4445.

He will tell you the 53 and 54 Powerglides are much harder to come by than the later years.