Recently discovered that the 10 bolt in my 66 is toast. I’m not going to dump money into that, but instead have sourced a 12 bolt
The issue I have is that it’s from a 67. From what I’ve found, it should fit into my car without modification. However, it appears that the upper control arms are longer on the 66 vs 67? What arms need to be used to make this work? Is the frame mounts different between the years or are the axle attaching brackets different? I already know that I need to add a 4th arm. Anybody done a swap like this before? Just trying to cover all the beses before I commit to buy the 12 bolt
Check the pinion angle on your 10 bolt and verify the 12 bolt matches when installed. If it doesn't the other control arms may be needed or you may need adjustable control arms to get the angle right.
hi can any one tell me the flange measurement from top hole to hole is it 3.375 on a 1966 12 bolt diff.
do a disc brake swap on the diff and using a mbm dbk1012 kit
You do not want a 12 bolt out of a truck. Uses different gears, has different axles with bigger bearings (hence the difference in size) to carry more weight (the purpose of a truck). Oh and the truck 12 bolt uses a different posi that will break first time you try to launch with slicks.
So since there is no use for a 12 bolt out of a truck except to put in a truck I didn't include it. Just use the dimensions for the car 12 bolt.
I swapped my single upper arm 10 bolt for a 12bolt about 2 years ago. (clutch dump burn-outs caused the pass. side axle tube to break its' spot-weld and rotate, which moves all those suspension mounting points. Really bad juju)
I used my stock lower control arms but I boxed them in and I had happened to order the Hotchkis adjustable Uppers, which also ensured proper pinion angle on my lowered ride. Great product from them BTW.
Hopefully you're replacing those control-arm bushings while you're at it on anything you re-use! :thumbsup:
BA I'm replace everything and boxing the control arms also just got a rear disc brake kit Rebuilt the 12 bolts with 3.55 and Eaton truetrac and new Adjustable Panhard rod also. once that's all in will start on the LS swap.
What upper arms did the OP wind up using? Im also finding this out now by going to a 12 bolt. I dont know which arms to use the short 10" or the longer 12" ones. The axle that came out of my car had the ears on top of the pumpkin(hillbilly owner before me did this) and only used one of the longer arms, but the bracket was welded onto the axle tube.
Control arm lengths differ by year of the vehicle, not by the rear end used under it. From memorory it was 1965-'66 had one length and the 1967-'70 cars had the other. I can not recall from memory who had which, short or long.
Both 10 and 12 bolt use the same length arms (with the ten bolt having only one upper control arm and the 12 bolt using two). Once you find out what year car you have you use the arms to fit that body. (if switching from a 10 to a 12 bolt you will need a mounting bracket that welds to the body as well as a new control arm to complete the install.
I recommend buying aftermarket control arms as they are stronger than the originals and adjustable on top. I will also warn you that the mounting brackets for the control arms are only spot welded on and they can be torn off when pulling a wheelie doing a nine second pass.
Big Dave
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