Hello, Happy Fathers Day. I have opportunity to purchase 1964 Pontiac Tempest stock rear end. Original owner unsure of ratio. What was standard in manual / auto transmissions. Are the upper control arm bushings on the 64 rear smaller than the upper rear bushings on my 1965 Skylark 8.2 rear? Can I still use my standard rear upper control arms or will I need different ones? Thanks, Robert
Happy Fathers Day to you as well. The 1964 Pontiac Tempest came with either a 215 inline 6-cyl or a 326 V8 (with either a 2-bbl or 4-bbl carb). Do you know which engine the Tempest you are looking to get the stock rear end from? And what engine do you have in your Skylark, and what is your rear axle ratio now? Why are you looking to replace the entire rear axle assembly? The 215 inline 6 cyl 3-speed & 4-speed manuals came with a 3.08 ratio rear differential. The 215 inline cyl automatic came with a 2.56 ratio rear differential, with 2.78 & 2.93 ratios optional. The 326 2-bbl V8 3-speed & 4-speed manuals came with a 3.23 ratio rear differential with a 3.08 ratio optional. The 326 2-bbl V8 automatic came with a 2.56 ratio rear differential with a 2.93 ratio optional. The 326 4-bbl V8 3-speed & 4-speed manuals came with a 3.36 ratio rear differential with 3.79, 3.90, and 4.30 ratios optional. The 326 4-bbl V8 automatic came with a 3.23 ratio rear differential with 3.79, 3.90, and 4.30 ratios optional. I believe the only difference visually between a Pontiac A-Body rear differentinal and a Buick A-Body differential is that the Pontiac has one additional web on each side of the differential (to make the case a bit stronger). Internals are generally interchangeable between 64-66 within the same ratio. As far as I understand, the upper control arm bushings at least for the 326 V8 Pontiacs and the 65 Skylark are identical. I'm not sure if the 215 inline 6-cyl rear differential is the same, but I think they are also identical. Lengths (hub-to-hub) are identical. Hope this helps.
Thank You That info is just what I needed. Helps a lot. My rear is 2.78 open. I can get Tempest rear at reasonable price and will redo with posi and better gearing for my 4 speed manual T-10. Robert
Does the Tempest have a different ratio than your 2.78 (i.e.; is the Tempest providing you the "better gearing" for your 4-speed manual)? If so, what are you looking to go to? And what engine do you have in your Skylark?
My motor is 300 SBB with 4 barrel. I don't have gearing info on Tempest rear. I will find out later today or tomorrow.
I don't know what the SBB stands for. But the 300 V8 4-bbl is the Wildcat 355. If yours is a 3-speed manual, the standard rear differential ratio would have been 3.08. If yours is a 4-speed manual, the standard differential ratio would have been 3.23. If yours is an automatic, the standard differential ratio would have been 2.78.
I see you already said you have the 2.78 rear axle ratio. Means you must have an automatic. If you change gearing, be aware of the transmission's setup for low and high stall (shift point and stator pitch switch spot. You may not like the axle if these aren't changed to work with it.
Then you have a close-ratio BW T-10 4-speed. Be aware of that vs. a wide-ratio 4-speed as you determine what rear axle ratio you wish to move towards.
You can’t ask about Pontiac and Buick rears without thinking about this (or at least I can’t). Patrick
My understanding is that all '64 a body rears have smaller bushings on the differential ears. I just bought bushings for my '64 Skylark and the other 6 bushings were about $8 each, while the 2 smaller ones were about $38 each. Made by Rare Parts. Limited vendors.
