Total rearend change out - The 1947 - Present Chevrolet & GMC Truck Message Board Network

flyinbass · 11-27-2003, 03:36 AM

I have a 1970 Chevy Longhorn that has a one-ton posi-track rear end. I want to put a stadard 3/4 ton in to replace it. My truck is a 350/350 turbo. Does anybody know what years of chevy trucks would fit? New to the site.

Longhorn Man · 11-27-2003, 03:49 AM

Welcome to the board.
As far as i know, the only rear that will swap directly with no mods is one from another Longhorn.
Why are you wanting to down grade? If your truck is a one ton than you would have the ho72, and a 3/4 ton would have the ho52. The gearing would be the same, just a weaker unit. (4.56 standard onless small block/auto...tehn 4.11 standard)

krue · 11-27-2003, 04:18 AM

Welcome to the board from South Mississippi.

Duallie · 11-27-2003, 04:54 AM

What is wrong with your 1-ton axle? Is it broken or does it make your engine spin too fast?

Mike C · 11-27-2003, 09:25 AM

The Longhorn should have the same 40" spring centers as the 4 wheel drive trucks. My 1970 GMC Longhorn parts truck has a Dana 60 in the rear. It also has 3.73 gears. Truck was originally equipped with a POwer Lok that is not there, so gears most likely have been changed.

Longhorn Man · 11-28-2003, 02:30 AM

4.10 and 4.57s are the only thing shown in my restoration catalog from GM, onless you get dauls, then a 5.14 gear goes in.
So if there is a 3.73, then it is not stock.

I do not remember the widths, but CrazyLonghorn has looked into it and said that the longhorn is all alone on spring perch width.

1969 GMC · 11-28-2003, 03:15 AM

Welcome to the board!

Quote:

Originally posted by Longhorn Man
If your truck is a one ton than you would have the ho72, and a 3/4 ton would have the ho52. The gearing would be the same, just a weaker unit.

correct me if I am wrong, but the ho52/72 are the same unit, except for the ho72 having larger brake drums. kind of like how in the '73 up models, both 3/4 and 1 ton had the 14bff out back (in most cases).

Longhorn Man · 11-28-2003, 03:33 AM

Nope, the bearings are stronger and the axle shafts should be stronger.
*I don't know this for a fact....but have been told*
As far as looking at them side by side, I believe they look the exact same.

Canada20 · 11-28-2003, 02:42 PM

the debate continues.

I thought the diff in the diffs was that an HO72 was for duallies and the HO52 was used on the single wheel 20 and 30 series trucks.

Greg

Duallie · 11-29-2003, 03:37 AM

I found a blurb in my Hollanders years ago that alluded to the HO52 having 2 pinions and the HO72 having 4 pinions.

11-27-2003, 03:36 AM	#1
flyinbass Registered User Join Date: May 2003 Location: Vail, Arizona Posts: 3	Total rearend change out I have a 1970 Chevy Longhorn that has a one-ton posi-track rear end. I want to put a stadard 3/4 ton in to replace it. My truck is a 350/350 turbo. Does anybody know what years of chevy trucks would fit? New to the site. __________________ Gary R70

11-27-2003, 04:18 AM	#3
krue Designated A-hole! Join Date: Mar 2003 Location: South Mississippi Posts: 36,450	Welcome to the board from South Mississippi. __________________ "If it ain't broke, fix it 'til it is!" Being stupid ain't illegal. We're Still Debt Free Except for the House!!! www.daveramsey.com 70 GMC SWB Stepside project "Green Booger" soon to be 6.0l/4l80e 93 S-10 "Poppaw's Truck"

11-27-2003, 04:54 AM	#4
Duallie Registered User Join Date: Feb 2001 Location: Nikiski, Alaska Posts: 477	What is wrong with your 1-ton axle? Is it broken or does it make your engine spin too fast? __________________ Just as if I knew what I was doin'

11-27-2003, 09:25 AM	#5
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,723	The Longhorn should have the same 40" spring centers as the 4 wheel drive trucks. My 1970 GMC Longhorn parts truck has a Dana 60 in the rear. It also has 3.73 gears. Truck was originally equipped with a POwer Lok that is not there, so gears most likely have been changed. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

11-28-2003, 02:42 PM	#9
Canada20 Registered User Join Date: Jun 2001 Location: Calgary, Alberta, Canada Posts: 802	the debate continues. I thought the diff in the diffs was that an HO72 was for duallies and the HO52 was used on the single wheel 20 and 30 series trucks. Greg __________________ No such thing as a stupid question, right?

11-27-2003, 03:49 AM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Welcome to the board. As far as i know, the only rear that will swap directly with no mods is one from another Longhorn. Why are you wanting to down grade? If your truck is a one ton than you would have the ho72, and a 3/4 ton would have the ho52. The gearing would be the same, just a weaker unit. (4.56 standard onless small block/auto...tehn 4.11 standard)

11-28-2003, 02:30 AM	#6
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	4.10 and 4.57s are the only thing shown in my restoration catalog from GM, onless you get dauls, then a 5.14 gear goes in. So if there is a 3.73, then it is not stock. I do not remember the widths, but CrazyLonghorn has looked into it and said that the longhorn is all alone on spring perch width.

11-28-2003, 03:33 AM	#8
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Nope, the bearings are stronger and the axle shafts should be stronger. I don't know this for a fact....but have been told As far as looking at them side by side, I believe they look the exact same.

11-29-2003, 03:37 AM	#10
Duallie Registered User Join Date: Feb 2001 Location: Nikiski, Alaska Posts: 477	I found a blurb in my Hollanders years ago that alluded to the HO52 having 2 pinions and the HO72 having 4 pinions. __________________ Just as if I knew what I was doin'



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