I'm thinking that car should have been a 455/TH400 setup from the factory. Definitely would have had a TH400 with the BBB. Not an A-body (GS/Skylark)
Thanks, it does have a 455, I wasn't sure about the trans. Looking at the engine plus trans for sale and didn't know what it had in back.
Should have a TH400, but there is a very slight chance it's a TH375-B, which is a TH350 with extra clutches (as opposed to a TH375, which is a TH400 with fewer clutches, and Buick didn't use). If the trans pan looks kinda like Texas, it's a 400. If it's square, it's a 350- or 375B
Yes - but it'd be a really, really odd duck if you didn't have a 400 in a Centurion. I only mentioned it 'cause it's just something to be aware of, and lots of people get the "intermediate" tranny's (375-B and 375) mixed up.
Thanks. So is it true that I can use any A body rear end in my 68 buick skylark? Do you guys know of any ones that typically came with posi rear ends? for future reference.
So is it true that I can use any A body rear end in my 68 buick skylark? pretty much. chevs will normally come with C-clip retainers in the pumpkin for the half-shafts. BOP's normally have the much better bolt in retainers out at the hubs. no worries about losing a wheel under hard accelleration if you snap a half shaft. :TU:
That's good to know, but I'm only interested in the tranny and engine. Tailshaft will come later. Been thinking about buying a new shaft to fit instead of finding an old one and cutting it up.
Ummmm... When he said "tailshaft" he IS talking about the transmission. There are "short shaft TH400s" and "long shaft TH400s." This refers to the back part of the transmission, the output shaft and its housing. The Centurion transmission is a long shaft TH400. It CAN be used in a 68 Skylark (A-body), but you will have to drill new holes in the frame to move the crossmember back. You will have to shorten the DRIVEshaft (probably what you thought he was talking about) anyway for a TH350 to TH400 swap, but you will shorten it a lot more for a long shaft TH400 vs. for a short shaft. Original TH400s in A body cars were short shaft
Any 68-72 A body (Chevelle, Le Mans/Tempest/GTO, Cutlass, Skylark) will bolt in. Your 68 Skylark has an 8.2" rear end. 71-72 Buick and Olds use an 8.5" rear end, which is stronger, but requires a slightly different length driveshaft.
1972 Buick Centurion Specifications Transmission, Standard: Turbo Hydro-matic 400 automatic Rear Axle Ratio: 2.93:1 Wheelbase: 124.0 :Smarty:
you will shorten it a lot more for a long shaft TH400 vs. for a short shaft. price for shortening the shaft will likely be the same no matter which length you go with. the advantage goes to the longer shaft though. a longer shaft will have less deflection at the U-joints and therefore less frictional losses and better delivery of torque to the rear. to ID a TH400 use the pics in this thread. a short shaft trans has no ribs on the top of the tail piece and a long shaft has two. http://www.teambuick.com/forums/showthread.php?t=9781
Since I have a 68 A body would you guys suggest using a short shaft or long shaft tranny or doesn't it matter either way? Is it easier to install using a short shaft?
Absolutely short shaft if you can find one. Then you won't have to drill holes in your frame. Even with the holes drilled, the crossmember mounts don't sit nicely on the frame like they should with a long shaft, because it is not a spot the factory intended the crossmember to be, and the frame is not quite flat where the mounts end up.
So with a short shaft TH400 I will not have to move the cross member even though it currently has a powerglide tranny?
