Technical 55 buick diff swap

Hey guys I'm in the midst of a 55 Buick special build. I've already purchased a 401 nailhead & T700 for it. It'll be bagged & a nice cruiser for my woman & I. However... I'm caught between 2 minds with the rear end. I'm gonna to fit a triangulated 4 link in myself & obviously I have to convert the rear end to open shaft. Has anyone ever tried to fit a later model centre to a std 55 Buick diff housing? I know many other HAMBers have a lot of access to chevy 10 bolts in the USA but I'm in Australia & they're not as common to come across. Am keen to keep the Buick 5 on 5 stud pattern. Anyone know if an early to mid 60s Buick diff (mate has one) would fit? Later one could take the power upgrade of the 401 I'm thinking. The std 55 diff axle to axle is around the 58" mark. Any info would be greatly appreciated!!!

 

You can use the centre you have, you might be able to use a 60-63 centre but watch the axle splines '55 is different to 60's . 50's (57 ish???) Ponti seem to get used a bit or its back to a 9"

 

The axle splines changed in '56 models. There are quite a few GM, and a few Ford, axles that have the 5x5 bolt circle. Pontiac and Oldsmobile used that for years....US Chevy full size 1971 thru 1976, '90s big Chev Caprice, Olds wagons and Buick Roadmaster sedan and wagon, 1971 up Chevy pickups, '57 thru '60 Mercuty, '73 thru '78 Ford and Merc, some Edsels.....

Since you are reengineering the rear suspension anyway, you will find it quite a bit easier to change the complete axle assembly than to convert to open drive.....IMO, of course.

 

Got my hands on a 9" diff & 3.55 LSD centre off a mate!!

 

If you decide to use another rear. You can redrill the rear bolts on the 10 bolt to 5 on 5 with a drill guide from HAMB'er rottenleonard. I got mine today. Whomever did my 49 Buick put a 5 on 4.75 rear in it and used unilug wheels. I didn't catch that detail until after I had painted my new 5 on 5's.

 

Does anyone have any experience adapting a 55 Oldsmobile or 55 Pontiac rear springs and rear axle to a 55 Buick frame?

 

A simple approach would be to get the rear end and trailing arms from a 60-72 chevy pickup (with coil springs). Adapting to Buicks is fairly simple. Only the panhard bar might need to be custom mounted.

 

The frame rail contours at the rear kick up on a Buick do not lend themselves very well to parallel leaf spring setup. It can be done by angling the front of the springs inboard, but you give up some roll resistance in the process. The GM "truck arm" suspension, mentioned d2 Willys' post above, is by far the most compatible and relatively easy to adapt to the Buick chassis.

In addition, the power from the axle is transferred into the X member as it is in the original Buick torque tube setup. Several threads on The HAMB dealing with this.

 

Thanks for the replies. I was just thinking of doing a easy rear end swap for when I do the engine/trans swap. I knew about the truck arm deal but wondered if there wasn't another way.