1957 Pontiac Transmission Replacement

[super]

Have a friend that owns a 1957 Pontiac. The slim jim is bad in the car and he is wanting to swap it with a Pontiac turbo 400. Any members swap transmissions in a car this year and what kind of adapter plate did you build or use.

This will be a budget swap. Don't want any $600 or $700 adapters.

Any info would be greatly appreciated. The car will be worked on quickly to get it ready for spring cruising. It was my friends father's car and he wants to get it on the streets again.

The '57 is currently running a 1958 370 with 1962 421SD "127" heads. Many good parts in the combination. Well over 400 horsepower.

Thanks.

[stevep]

The 57 has a Dual Coupling Hydramatic, not a Slim-Jim.

The latest trans that you can use behind a 55-60 motor is a 60 unless you use an expensive adapter as the bellhousing shape and bolt pattern are different than 61-79. Nothing other than a 55-60 Pontiac trans will bolt to a 55-60 motor (without an adapter.)

I an also curious to see if someone has made an adapter to do this.

[super]

Thank you very much for the reply. I will let my buddy know A.S.A.P.

I imagine he will start doing his homework and try to build an adapter. I am sure there will be a lot of time and headaches, but the finished product will be well worth it.

Have you seen any '57's running a newer model transmission?

We do have another 1958 370 block, so at least he can layout the template for an adapter outside the car. Once he gets something built, he will have a great cruising machine.

Thanks.

[stevep]

Another thing to remember is that the snout of a 55-63 crank was not made to accept the pilot of a torque converter.

[super]

I noticed on kits such as the one listed in the tech section on Larry's site the kits had an adapter on the crank. Noticed the adapter was thick as well, which I am sure was to help acommodate the adapter on the crank. Correct?

Good thing my uncle has a machine shop. I am sure my friend will be working with him closely on several things.

thanks

[stevep]

I have never actually seen one of these kits, but it makes sense to me.

[Larry]

For those who want to read the article on transmission adpters, here is the article link in our On-Line Magazine: http://www.pontiacregistry.com/members/online_magazine.php?view=1&article=56

I would think that your friend would be able to make a bunch of extra green by marketing any adapter that he comes up with. It is an age-old Pontiac problem getting the newer transmissions in the older cars.

Please keep us posted on the progress.