66 f85 rear end swap ?'s
April 12th, 2015, 07:15 PM
#1
66 f85 rear end swap ?'s
i have a 66 f85 and i got a 71 chevelle rear end, posi and gears for free. i already did research on the swap but i have a few things left un clear. the rear end in my car is the same width as the 71 so im not concerned about that, but my car has bolt in lower springs and the 71 has the raised cup, ive read that my springs will work and that they wont. And will i need a different length drive shaft?
April 12th, 2015, 08:45 PM
#2
Ben
Join Date: Mar 2009
Location: Snohomish, WA
Posts: 1,825
As long as you use your existing springs on that rear, you'll be fine.
The spring difference is in the top of the springs. 64-66 have rear springs with an "open" top loop. 67+ they have "closed" or behive style rear springs, so the upper perch on 67+ frames is different.
But the rear axle perches are essentially the same. 64-66 they were flat & used the retainer to hold the spring down, 67+ they had a bump that kept the spring in its place.
Unsure about the driveline length differences...
Hope this helps!
The spring difference is in the top of the springs. 64-66 have rear springs with an "open" top loop. 67+ they have "closed" or behive style rear springs, so the upper perch on 67+ frames is different.
But the rear axle perches are essentially the same. 64-66 they were flat & used the retainer to hold the spring down, 67+ they had a bump that kept the spring in its place.
Unsure about the driveline length differences...
Hope this helps!
April 12th, 2015, 09:56 PM
#3
so my spring should sit over that cup instead of bolting on my existing rear end? cool. i tried measuring from the axle tube to the u joint on the two rear ends but was hard to get a measurement on the one under the car. The 4.11 posi is going to be a lot more fun than the 2.73 open!! and the t56 1st gear doesnt seem to like the 2.73 unless my engine is just a wimp
April 14th, 2015, 10:04 AM
#4
Registered User
Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,737
Spring...right and wrong
Yes, the spring will work...BUT the 64 -66 spring is slightly different larger lower diameter and will slide around on the chevy raise spring perch perch. You can use a rubber isolator to take up some slop . The 67-72 are slightly smaller lower diameter spring coil.
the upper 1964-1967 are all the same 6' big diameter pocket in the cross member frame . the 68-72 you can actually flip the spring upside down and it will fit either way.
You will not need to change drive shaft...Same length BUT you will need to change u-joint to a 372 moog (chevy to BOP conversion joint found at any auto part store. They can cross reference that moog number to spicer or neapco etc.
Jim
JD
the upper 1964-1967 are all the same 6' big diameter pocket in the cross member frame . the 68-72 you can actually flip the spring upside down and it will fit either way.
You will not need to change drive shaft...Same length BUT you will need to change u-joint to a 372 moog (chevy to BOP conversion joint found at any auto part store. They can cross reference that moog number to spicer or neapco etc.
Jim
JD
April 14th, 2015, 10:11 AM
#5
i have a chevy driveshaft in it now so im just using a regular chevy u joint. found out i have a 2 series carrier and the 4.11 gear wont work. i already pulled my old rear end out too...
April 15th, 2015, 04:05 AM
#6
Registered User
Join Date: Jul 2006
Location: Richfield, Oh
Posts: 1,737
Thread
Thread Starter
Forum
Replies
Last Post
350TurBRO
Transmission and Driveline
6
September 12th, 2014 11:52 AM
