Technical 348 Transplant: Transmission Suggestions

I've recently purchased a '58 Parisienne that is a 261 & Powerglide car. I've picked up a rebuilt '61 Pontiac 348 and will be doing an engine swap soon. It's my understanding the 6 cylinder iron Powerglide will not work with the 348? What would be recommended for a transmission? Aluminum Powerglide? Turbo 350? 700R4? I'd like to keep the swap as simple as possible. I've got a 58 V8 parts car that I can salvage the engine mounts from. Thanks in advance.

 

Overdrive for sure

 

What am I going to need to consider if I go with a 700R4?
Will I need to change the yoke on the driveshaft?
Will I need to have the driveshaft shortened/lengthened?
Relocate the crossmember?
What flexplate and torque convertor?
What do I do about the shifter cable on the 7700R4 vs. the current shifter linkage?
Will I still be able to have a kickdown?

Is there a better OD option than a 700R4?

 

700R4.

It has a nice low first gear to get that ship underway.

 

You will need a different transmission yoke, as is the case with any option.
You will need to have your driveshaft shortened, as is likely the case with any option.
You will need to move the crossmember, as will all options.
The flexplate will need to match the tooth count that the starter for the 348 needs.
The torque converter is specific to a 700R4, it has a lock-up clutch in it. A stock stall speed should be fine.
You should be able to do some minor modifications to your existing shifter linkage to get it attached. I cannot say if you will be able to access 1 and 2 in the shifter pattern with the existing shifter without additional modifications, but you should be able to get P, R, N, OD, and D.
The 700R4 has a Throttle Valve cable (TV). While it does indeed provide kickdown functions, it is very dangerous to think of it as that. It controls the line pressure in the transmission. As such, it needs to be set up properly. That's not hard to do. Being careless and not doing it properly will kill the transmission by the second stop sight that you reach, on the first test drive.

The 2004R would work too, but they are getting harder to source. Also, it does not have the same deep first gear that would be of benefit here.

 

If simplicity is your goal I’d go TH350 but with a little more effort the 700R4 is a great driving and cruising trans. The overdrive is really nice.

 

If the floor pan/tunnel has room 700r4. if not 200r. The od trans is the best money I ever spent on my El Camino. 20% mileage gain over th350. Also want 3.0 to 3.25 rear axel ratio.

 

The cast Iron Powerglide was a little chonky in the middle. There might be room for a 700R4 where it was.

 

Do you know the rear gear ratio you have now? I/e I have a pu with 3.08 rear, with 28/29 inch tall tires. I don’t have a need for an OD transmission.

 

“rebuilt Pontiac 348”

 

200 r -4

 

Yes, and he's not incorrect.

The 348 was an available engine in a 1961 Pontiac Parisienne, just no bowtie on the valve cover.

 

???

 

Thanks. Beat me to it. lol

…… and a 58 Parisienne.

 

"I've picked up a rebuilt '61 Pontiac 348 and will be doing an engine swap soon."

If it did not have Chevrolet-specific valve covers, your statement could be 100% true.

 

A Parisienne just looks like a Bonneville; its Canadian.

 

I put a 200 R4 behind my 348.

 

turbo 350 .....

 

Agreed. Lots happens in 64 years. Pontiac 348’s had smooth covers. I’ve got a set on the way.

 

That 348 is going to be hard to make look Pontiac!

 

My ‘58 Chevy convertible ended up with a Dual-range Hydramatic behind a 3-carbed 348 - that big heavy car launched really nice!

……really impractical combination today…….

 

He has smooth covers on-the-way. That was the only difference when it was found in the Pontiac, except for maybe the air cleaner sticker.

 

As a bit of an educational exercise, in the 50’s…… and running until I think the early 70’s, due to Canadian tariffs, GM Canada built its own line of Pontiacs. The Parisienne was one of them. Started in 58, it was built on a Chevrolet chassis with most Chevrolet engine options other than a 261 6 cylinder rather than a 235. The Parisienne really is a Bonneville on a smaller Chevrolet chassis. Other cars unique to Canada off the top of my head are the Beaumont (Chevelle) and Acadian Canso (Nova).
Here’s a beautiful ‘58 Parisienne convertible with 348.

 

I didn’t realize that the 348 was in Pontiacs also.

 

They, and the later the 409, got snuck in there.

 

It’s funny how GM got into trouble in the seventies for doing the same thing, putting chevy and Olds engines in Pontiacs and Buicks.

 

I’d put a 3 speed auto or a 3 OD behind the the 261 with an adapter from Buffalo Enterprises. A 261 divided by 6 equals 43.5 times 8 equals 348. Sounds reasonable for a Inliner to me…

 

There’s a 409 Pontiac for sale up here right now. Under $60k CDN. Would be under $50k US.

For comparison, here’s my ‘58 Parisienne convertible and my ‘58 Impala….. both on the same chassis.

 

That’s good math!