VCCA Home Forums TECHNICAL - 1945 AND NEWER 1965-1970 Rear end interchangability 1965 to 1967 IMPALA

Hi all,
I have a 1965 IMPALA rear axle assembly and i was wondering if i can use it in a 1967 chassis which i have just bought.

I am aware that the 1967 has shorter upper arms, and that this may affect the alignment of the pinion angles and tailshaft.

Are the lower trailing arms the same length.?
Or do i have to use the 1967 housing in the 1967 chassis and repair it.
Thank you everyone , Jack

Hi Jack,
'65-'70 rear axles inter change no problems at all.Outside of the uppers,should be a direct bolt in.Lowers are same length.I've swapped out a few over the years with no hassles.The frames from '65-'70 full size passenger B cars are same(except wagons).
Hope this helps,Jim

Sorry got lazy when I said axles,I mean entire rear differential.

Thanks Jim.

Regards Jack

Your welcome.Are you doing a straight change out?IE-a 10 bolt for 10 bolt?

Hi Jim,

Yep that gets confusing sometimes, rear axles, differentials, axle shafts , the whole rear axle assembly was it.

So , because the upper arms are shorter in 67-70 models, doesn't that pull the the upper side of the axle housing forward, and push the pinion down? Or did they lengthen the front pivot bracket which attaches the upper arms to the chassis?

thanks Jack

It is 12 bolt to 12 bolt.
I have just bought a 67 chassis to replace the chassis in my 65.already blasted and painted.

As my car was changed to rh drive back in 1990, it is sitting on a RH drive 1966 chassis which i swapped , but there has always been a bad front end alignment , as the chassis is about an inch shorter on the rh wheel base. I have seen other
rhd 1966 chassis the same ,they must have been assembled badly down here.
So the 1967 chassis will fix that problem, and then i will have the newer design drag link and front steering changes as well.

"So , because the upper arms are shorter in 67-70 models, doesn't that pull the the upper side of the axle housing forward, and push the pinion down? Or did they lengthen the front pivot bracket which attaches the upper arms to the chassis?"

Jack,
I know there were several different length upper trailing arms for 65-70 12 bolt assemblies.The lowers are the same.I do not recall the specific length for upper trailing arms for 67-70.This is where deep research comes into play<g>.I will do some digging for you as soon as I can.I would start with the factory assembly manual and service manual,though. Jim

I changed the complete rear end in my 70 convertible a few years back from a 10 bolt posi to a 12 bolt out of a 68 impala. It all bolted right in with no problems.

Same here,Olds51.
I've swapped out rear ends like for like on 2 separate occasions on '65-'70 B cars and had same direct bolt in results as you did.
I do know of at least one person who ran into upper control arm length issues,though. Jim

When I get the chassis out from under my car car i will measure the lengths of the 1965 to 1966 upper arms, as well as the lengths of the 1967 arms to give a comparision.
A 1967 to 1970 should be a straight swap, as 1967 was the change year for the upper arms.
I will post the diagram of the change when i get a chance on the week end .

I have the pictures posted in the members photos forum.

Good catch,Jack.I have this article as well in an Impala book.I knew there was a difference in arm lengths but wasn't sure of year change.
That explains why a friend had alignment issues trying to put a '65 12 bolt under his '69.I had no alignment/pinion angle issues when I did a '68 12 bolt under a '70.
Thanks and good luck with your project! Jim

Well, i finally managed to measure the 1965 - 1966 upper rear trailing arms, They are 13" long centre bolt to centre of bolt.
The 1967-68( 69 & 70) upper rear arms are only 10 inches centre of the bolt to centre of the bolt.
Quite a difference.