I have done a lot of research on putting an 8.5" 10 bolt in a 66 "A" body and still am not sure what fits and what doesn't and what mods are required.
Other than knowing for sure the driveshaft needs to be shortened I have read conflicting sources that control arms would not fit due to angle variations as well as location.
Could someone please post what casting number and/or year and make of vehicle that will work with this swap and what actual changes are required?
66 pontiac "A" body 8.5" swap
Re: 66 pontiac "A" body 8.5" swap
ALL A-body GM rears are interchangeable. 1964-1972
Difference between these rears would be width -
These rears interchange 54.25 width
1964-1967 chevy
1964-1966 Buick- Olds- Pontiac
These rears interchange 55.25 width
1968-1972 chevy
1967-1972 Buick Olds Pontiac
U-joints will need to be swapped from chevy 1 1/16 cup to BOP 1 1/8 cup u-joint rears
1971-1972 Cutlass and Buick A-body have the 10 bolt 8.5 rears which if installed in any other non 8.5 car will require a driveshaft shortening and u-joint swap if installed in a chevy.
Now the 10 bolt 8.5 into your 1966 -
If you have a LATE 66 the rear might already be 55.25 and you will really not need to do much as the width will be the same and all control mounting points are identical. Drive shaft will need to be shortened, U-joint will be the same, brakes are the same.
If you find that your 66 rear is still the narrow 54.25 you MIGHT need to deal with outer fender clearence problems if you are using over sized tire on the car. Putting another 1" negative backspacing on the rims if you are buying NEW ones will solve this problem.
Hope this answers the question.
Jim
J D Race
Difference between these rears would be width -
These rears interchange 54.25 width
1964-1967 chevy
1964-1966 Buick- Olds- Pontiac
These rears interchange 55.25 width
1968-1972 chevy
1967-1972 Buick Olds Pontiac
U-joints will need to be swapped from chevy 1 1/16 cup to BOP 1 1/8 cup u-joint rears
1971-1972 Cutlass and Buick A-body have the 10 bolt 8.5 rears which if installed in any other non 8.5 car will require a driveshaft shortening and u-joint swap if installed in a chevy.
Now the 10 bolt 8.5 into your 1966 -
If you have a LATE 66 the rear might already be 55.25 and you will really not need to do much as the width will be the same and all control mounting points are identical. Drive shaft will need to be shortened, U-joint will be the same, brakes are the same.
If you find that your 66 rear is still the narrow 54.25 you MIGHT need to deal with outer fender clearence problems if you are using over sized tire on the car. Putting another 1" negative backspacing on the rims if you are buying NEW ones will solve this problem.
Hope this answers the question.
Jim
J D Race
J D Race
Re: 66 pontiac "A" body 8.5" swap
Thank you so much for the great explanation, this clears things up so thank you!
Do you have a catalogue on your site or do I just need to contact you with what I am looking for and prices? I have not found an actual catalogue with part numbers and prices.
Thank you
Do you have a catalogue on your site or do I just need to contact you with what I am looking for and prices? I have not found an actual catalogue with part numbers and prices.
Thank you
Re: 66 pontiac "A" body 8.5" swap
There are Sooo many combinations to build a rear we just take them all as individuals. You can contact here when your ready or use the phone number at the top right hand of the home page.
J D Race
Re: 66 pontiac "A" body 8.5" swap
Hi jim, i too am swapping an 8.5 into a 66 a-body. Mine is an olds cutlass. Ive read somewhere that the spring pads are different for the 71-72 rears than whats used on the 66's?
Also, whats to torque spec for the axle retaining hardware, the bolts that hold the axle retaining bolts? And should the axle seal get some kind of gasket material spread on it?
Thank you
Dan
Also, whats to torque spec for the axle retaining hardware, the bolts that hold the axle retaining bolts? And should the axle seal get some kind of gasket material spread on it?
Thank you
Dan
Re: 66 pontiac "A" body 8.5" swap
1964-1966 (EARLY) SPRING PERCHES ARE FLAT AND REQUIRE A CUP WITH BOLT AND NUT TO RETAIN THE LOWER SPRING ON THE AXLE SHAFT. this PERCH IS STILL IN THE SAME AREA AND THE LOWER SPRING DIAMETER ON THE EARLY GM a-BODY S IS SLIGHTLY LARGER COIL THAN THE RAISED SPRING PERCH 67-72 GM A-BODY LOWER SPRING COIL.
Axle retaining plate bolts require only 20-30 foot ponds of torque but really just tighten them with a 3/8 drive as tight as you can and you will be good.
NO gasket really is required..GM did use a variety of composite and tin type gasket material... there is no real sealing need for these gaskets. WE can only assume it helps keep the backing plate from rusting to the flange etc.
One the 70 71 72 it actual can cause end play issues as the distance is quit critical with the a9 tapered bearing system. Do not use gaskets on these years.
Jim
JD
Axle retaining plate bolts require only 20-30 foot ponds of torque but really just tighten them with a 3/8 drive as tight as you can and you will be good.
NO gasket really is required..GM did use a variety of composite and tin type gasket material... there is no real sealing need for these gaskets. WE can only assume it helps keep the backing plate from rusting to the flange etc.
One the 70 71 72 it actual can cause end play issues as the distance is quit critical with the a9 tapered bearing system. Do not use gaskets on these years.
Jim
JD
J D Race