Leaf spring perch variations???
 

I have removed two rear differentials out of leaf spring 1970 2wd trucks. One 6 lug chevy and an 8 lug gmc. Both the perches on these diffs measure 42.5 inches center to center.

I have had a couple of people interested in purchasing these for different trucks. One had a 1965 chevy 4x4 and his perches measured 40.25 inches center to center so they wouldn't fit.

Another guy measured his 1971 4x4 blazer perches and they were also 40.25 inches center to center.

My question is were all 4x4 differentials set at the 40.25 inch setting and 2wd diffs set at 42.5 for our 67-72 trucks?

I could use an education!!! Thank in advance for your insight.

Re: Leaf spring perch variations???
 

I can't believe there have been no comments or information on this thread. Is it to boring to get any input on?????

Re: Leaf spring perch variations???
 

Yes, 2wd is 42.5" center to center and c30/cab & chassis/4x4 are 40" center.

Re: Leaf spring perch variations???
 

73+ axles:
2wd and K10-K20 are 42.5 centers
C30/K30/c&c are 40" centers

Re: Leaf spring perch variations???
 

I concur with the above. 40.5" on 67-72 4x4 and 42.5" on
73 and up 1/2 and 3/4 ton with the K30 at 40.5".

The '69-'72 4x4 trucks also use 2 1/2" wide leaf springs and the 2x4 use 2" wide springs. Longhorn trucks are 2 wheel drive but they have 40.5" spring centers and use 2 1/2" springs just to mix things up.

Not a '67-'68 guy so can't speak to what they had but I know the springs are different.

Re: Leaf spring perch variations???
 

Weren't the 73+ axles also wider than the 72 and down?

Re: Leaf spring perch variations???
 

I don't think so. 4 Wheel Parts shows replacement axle the same for '70-'81 8 7/8" axle.