1956 Buick Roadmaster - motor & transmission changes

[Guest Grandma's 56]

We currently have a 56 roadmaster with a 322 Nailhead motor and a danaflow automatic transmission. I'm looking at replacing the current engine (rusted completely and not working) with either of these that I'm looking at: a 64 355 Wildcat Motor and the other is 64 401 Nailhead. Will either of these motors hook up to the existing motor mount area and my current transmission?

Which would be easier? I can buy the 401 with the tranny or I can buy the 55 with the tranny as well. But I want to know if I can keep the original transmission because it's been rebuilt.

I'm new to the club and to the forum - but would appreciate any feedback. Thanks.

[JohnD1956]

First off, welcome to the Forum and welcome to the Buick Club.

Now the bad news. I do not believe you can use either the 1964 300 or the 64 401 with the existing transmission. While there may be an adaptor available I have not heard of one being advertised.

Also note, if you change to the 401 with a newer transmission you'll need to change the rear axle which is doable, but a lot of work. The original 56 setup is a "Torque-Tube" driveline, also known as a closed drive line. The rear axle is bolted to the torque tube and is not flexible like an open driveshaft. The driveshaft is inside the torque tube and the U joint is actually inside the rear housing of the transmission.

The rear axle is held in place by the rear shocks and the cross bar behind the rear end, also known as the Panhard bar. There are no trailing arms.

Virtually every other open rearend requires trailing arms for attachment. So, to put in a new rear axle you'll need to weld in braces to hold trailing arms.

This has been done by many, but it will take an experienced person to complete the work.

Edited September 19, 2011 by JohnD1956 (see edit history)

[Pete Phillips]

You need to stick with a 322, 364, or 401 from 1960 or earlier. After 1960, the Buick engines do not mate up to a torque tube or enclosed drive shaft, which is what the '56 has.

Pete Phillips, BCA #7338

Leonard, TX

Edited September 20, 2011 by Pete Phillips (see edit history)

[sean1997]

Yes, you can keep the original transmission, but you will need to use a '57-'63 Dynaflow bellhousing and front pump and a '59-'63 401 from a Dyanaflow car. Contact Tom Telesco for all the details as he has done this exact swap on his '56. His contact info is listed below:

Tom Telesco

Classic & Muscle Automotive

465 Glenbrook Rd.

Stamford, CT 06906-1820

203-324-6045

Or see him on v8buick.com, teambuick.com, and jalopyjournal.com (HAMB) under the user ID of telriv.

[MrEarl]

I bet Grandma would say save yourself a heap of work and trouble and find a '56 322 and tranny to put back in it. 322's are awesome engines and they can be found. In fact I am looking for a good one myself, just the engine.

When you say your existing one is "rusted", what ya mean "rusted". Is it stuck and won't turn or what?

by the way, welcome aboard. sounds like you may want to hang around here awhile. http://forums.aaca.org/f115/please-introduce-yourself-290500-11.html#post917514

also I'd like to encourage you to join the Buick Club of America. Great club and an awesome monthly magazine 'The Bugle'. https://www.buickclubofamerica.org/subscribe.html If you do join, I'd be honored to be listed as the "referring member"

Edited September 19, 2011 by MrEarl (see edit history)

[Guest 54fins]

Mr earl is right on. If you deviate from a 322 setup, you now have a very major project. Let's look at it in time and money. There is alot of 322 drivetrains available fairly cheap (depending on your definition of cheap). Let's say it is the path of least resistance.

Once you start going modified, Then it's a really a hot rod project and a whole different ball game. The dynaflow is your limmiting factor, you may as well stay "correct" on the engine as you won't make the car perform any better, and a correct engine won't be any more $$ than a non correct engine. Once you go modified, you may as well update the tranny and suspension too.