Rear End Width Information?

[1965chevyc20]

Is there a source/sources for determining axle width: Wheel Mounting Surface (WMS) to WMS for Chevy/GMC vehicles?

[dwcsr]

Outside Width Year Model
57.75 1962-1964 Chevy II/Nova
57.75 1965-1967 Chevy II/Nova
58.00 1978-1988 Chevy Malibu, Monte Carlo
59.50 1968-1982 Corvette
60.00 1955-1964 Chevy car
60.00 1967-1969 Camaro
60.25 1968-1979 Chevy II/Nova
60.50 1984-1995 Corvette
60.50 1964-1967 Chevelle
62.00 1955-1959 Chevy pickup
62.50 1968-1972 Chevelle
61.00 1970-1981 Camaro/Firebird

[1965chevyc20]

That's great! How about a 65 Chevy pick up?

[Captainfab]

I assume you are talking about the Eaton HO52/72 in a C20? If so it should be aprox 65.5" WMS to WMS. A '73 and up 10.5" FF 14 bolt is aprox 66.875" WMS to WMS.

Originally Posted by 1965chevyc20

That's great! How about a 65 Chevy pick up?

[66-PMD-GMC]

Speaking 1/2 ton 2wd 12 bolt diff's.
How does someone identify what year diff that they are looking at?
Stamp? Casting number?

What are the year groupings?
60-62 housings are different than 63 and up...
63 ... the bastard child?
64-69 ?
70-81 ( I know this one as I have a new set of axles in the box)
81-88 ?
Where can in find and confirm this info?

Everywhere I look for info on the 12 bolts, all I find is car info which doesn't apply...
Any help?

[Captainfab]

The '60-'62 Chevy C10's had the Eaton HO32 and they measured 62" WMS to WMS. I do not know what the width is of the Dana 44 that came in the GMC's.

The truck 12 bolt first was available in the '63 model year, and had pressed on backing plates for that year only. The '63 and '64 12 bolts had 17 spline axels and corresponding spider gears. From '65 and up, the axles were 30 spline. The 12 bolts were 62" WMS to WMS from '63 thru mid year 1970 when they increased to 63.5". The width remained the same thru the last year of the 12 bolt in '82. The 8.5" 10 bolts which were used from 1979-80 thru '87 (thru '91 for the V and R series) were also 63.5" wide. I have never paid any attention to and casting number differences, I just measure them if I am unsure.

[66-PMD-GMC]

Originally Posted by Captainfab

The '60-'62 Chevy C10's had the Eaton HO32 and they measured 62" WMS to WMS. I do not know what the width is of the Dana 44 that came in the GMC's.

The truck 12 bolt first was available in the '63 model year, and had pressed on backing plates for that year only. The '63 and '64 12 bolts had 17 spline axels and corresponding spider gears. From '65 and up, the axles were 30 spline. The 12 bolts were 62" WMS to WMS from '63 thru mid year 1970 when they increased to 63.5". The width remained the same thru the last year of the 12 bolt in '82. The 8.5" 10 bolts which were used from 1979-80 thru '87 (thru '91 for the V and R series) were also 63.5" wide. I have never paid any attention to and casting number differences, I just measure them if I am unsure.

Thanks, Interestingly, the 62 chassis I have came with a 12 bolt.
But now, because of your help, I can find the correct housing... Unfortunately I scrapped the old housing without measuring it

[nikwho]

Originally Posted by dwcsr

Outside Width Year Model
57.75 1962-1964 Chevy II/Nova
57.75 1965-1967 Chevy II/Nova
58.00 1978-1988 Chevy Malibu, Monte Carlo
59.50 1968-1982 Corvette
60.00 1955-1964 Chevy car
60.00 1967-1969 Camaro
60.25 1968-1979 Chevy II/Nova
60.50 1984-1995 Corvette
60.50 1964-1967 Chevelle
62.00 1955-1959 Chevy pickup
62.50 1968-1972 Chevelle
61.00 1970-1981 Camaro/Firebird

For whomever finds this post via a search, I wanted to point out an important correction. The 2nd gen Camaro's ('70-'81) have a 62.5" axle width, not the afforementioned 61". That's a significant difference and could cost some folks a bit of money and frustration.

Here's a good rear end width list that I've frequented:
https://www.google.com/amp/s/m.roadk...ican-cars/amp/

Nik