rear end widths - The 1947 - Present Chevrolet & GMC Truck Message Board Network

sick69 · 03-12-2009, 09:04 AM

So I've been looking at rear end widths and have done a search for the numbers.

The search resulted in ALOT of wheel back spacing Q&A but thats not what I'm looking for.

So here is the question,,,,,

What is the rear diff width on our trucks? I know the 67-69 is approximately 1.5" narrower than the 70-72's.

I've read somewhere the 70-72s are 64 1/8" from wheel mount to wheel mount. Is this correct?

67-69= 62 5/8" ?
70-72= 64 1/8" ?

Just double checking my double checking before I get myself in trouble.

Thanks guys,
Frank

**Tim Christian** · 03-12-2009, 09:43 PM

I do not have the measurments in front of me but 67-69 is same length and 70-72 is the same length.

sick69 · 03-13-2009, 12:39 AM

Ok thanks Tim

Can anyone comfirm the numbers above?

abadsvt · 03-13-2009, 12:55 AM

It has been a little while since i did my own investigating but if I am not mistaking the 67-69 rear ends are 56.5" wide from flange to flange and the 70-72 are 58" flange to flange. Hope that helps.

sick69 · 03-13-2009, 03:12 AM

Do you mean backing plate to backing plate? I'm looking for wheel mounting surface to wheel mounting surface.

sick69 · 03-13-2009, 03:27 AM

This might help,,,,,

OARNGESI · 03-13-2009, 03:33 AM

Why is the 70 to 72 rearends wider i thought that 1.5 inches is to compensate for disk brakes didnt disks come in 71

sick69 · 03-13-2009, 04:46 AM

Starting in 71 the trucks came with disk brakes in the front. Not sur why the ealier rear ends are narrower.

Frank

**clay68c10** · 03-13-2009, 08:00 PM

I think the older rear drums were narrower.

ERASER5 · 03-13-2009, 11:16 PM

70 was the change over year for the rear width. Some are wide, some are narrow.

Back to the original question, what is the measurement? I need to change the oil in the truck tomorrow, I'll try to measure my 12 bolt (1970) and the D-60 (1969).

**chev-obsession** · 03-14-2009, 12:56 AM

Quote:

Originally Posted by clay68c10

I think the older rear drums were narrower.

this is true

coast2coast · 03-19-2009, 07:27 PM

Anyone come up with confirmed numbers?

sick69 · 03-20-2009, 06:11 PM

I haven't found the answer yet,,,,so I dunno.

Frank

ERASER5 · 03-22-2009, 11:03 PM

Here are my numbers. I measured from wheel mount surface to wheel mount surface.

1970 GMC 1/2 ton truck long fleet with leaf springs

64-1/4" Front with 73-87 disc conversion

63-3/4" GM 12 Bolt 1970

62-3/8" Dana 60 1969

I have a 72 also, but the width will not be any narrower than the 70.

You can see that the new disc conversion is only 1/2" wider than the original rear, or 1/4" each side.

The D-60 is almost 2" narrower or 1" each side.

Does this answer you question?

sick69 · 03-23-2009, 08:22 AM

Yes actually it does. Thank You! The front measurement was never a concern, but those rear end measurements were the numbers I was looking for. I need to be in the 57"-58" range to run a 12" wide wheel and still have it fit in the wheel well.

Thanks again,

Frank

72BlckButy · 03-23-2009, 08:33 AM

This is a great thread... add this one to the file.

ERASER5 · 03-23-2009, 04:46 PM

No problem. I was researching rear widths as well as a number of other measurements for a swap I am preparing to do. I want it to go smoothly so I am measuring 10 times!

sick69 · 03-23-2009, 04:57 PM

That 70 12bolt,,,was it a coil spring rear end?

Frank

ERASER5 · 03-23-2009, 08:51 PM

"1970 GMC 1/2 ton truck long fleet with leaf springs"

I have not moved enough winter junk to get to the 72 Chevy with coils, but it should be the same as the 70.

By the way, tell Dieselarmy to quit shooting at you! LOL

03-12-2009, 09:04 AM	#1
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	rear end widths So I've been looking at rear end widths and have done a search for the numbers. The search resulted in ALOT of wheel back spacing Q&A but thats not what I'm looking for. So here is the question,,,,, What is the rear diff width on our trucks? I know the 67-69 is approximately 1.5" narrower than the 70-72's. I've read somewhere the 70-72s are 64 1/8" from wheel mount to wheel mount. Is this correct? 67-69= 62 5/8" ? 70-72= 64 1/8" ? Just double checking my double checking before I get myself in trouble. Thanks guys, Frank __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub Last edited by sick69; 03-13-2009 at 03:11 AM.

03-12-2009, 09:43 PM	#2
Tim Christian Senior Member Join Date: Dec 1999 Location: TN/VA Posts: 6,388	Re: rear end widths I do not have the measurments in front of me but 67-69 is same length and 70-72 is the same length.

03-13-2009, 12:39 AM	#3
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths Ok thanks Tim Can anyone comfirm the numbers above? __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

03-13-2009, 12:55 AM	#4
abadsvt Senior Member Join Date: Aug 2006 Location: Atascadero, CA Posts: 1,152	Re: rear end widths It has been a little while since i did my own investigating but if I am not mistaking the 67-69 rear ends are 56.5" wide from flange to flange and the 70-72 are 58" flange to flange. Hope that helps. __________________ (Project truck) 1970 C10 under complete transformation My current build thread http://67-72chevytrucks.com/vboard/s...d.php?t=212871 Other project: C5 corvette swap into 70 c10 http://67-72chevytrucks.com/vboard/s...=1#post2413517 On Hold

03-13-2009, 03:12 AM	#5
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths Do you mean backing plate to backing plate? I'm looking for wheel mounting surface to wheel mounting surface. __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub Last edited by sick69; 03-13-2009 at 03:12 AM.

03-13-2009, 03:27 AM	#6
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths This might help,,,,, __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub Last edited by sick69; 07-01-2009 at 09:09 AM.

03-13-2009, 03:33 AM	#7
OARNGESI Registered User Join Date: Sep 2008 Location: CASA GRANDE AZ Posts: 4,276	Re: rear end widths Why is the 70 to 72 rearends wider i thought that 1.5 inches is to compensate for disk brakes didnt disks come in 71 __________________ 70 SWB STEPSIDE 70 BLAZER 09 challenger

03-13-2009, 04:46 AM	#8
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths Starting in 71 the trucks came with disk brakes in the front. Not sur why the ealier rear ends are narrower. Frank __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

03-13-2009, 08:00 PM	#9
clay68c10 Senior Member Join Date: Aug 2004 Location: Centennial, CO Posts: 2,935	Re: rear end widths I think the older rear drums were narrower. __________________ ClusterTruck: 68 C10 Bought in 89, wrecked in 03. Slow low $ rebuild started '17. 6.0 & TKO http://67-72chevytrucks.com/vboard/s...d.php?t=788602 93 K1500 Short Step, 350, NV4500, EBL flash ECU. Vortec heads & roller cam someday... 05 Jeep Wrangler Unlimited. 3” lift & 6-speed 02 E320 the insurance total “free car” 13 Tahoe LTZ

03-13-2009, 11:16 PM	#10
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: rear end widths 70 was the change over year for the rear width. Some are wide, some are narrow. Back to the original question, what is the measurement? I need to change the oil in the truck tomorrow, I'll try to measure my 12 bolt (1970) and the D-60 (1969). __________________ '70 GMC C1500 LWB Power disc brakes. WooHoo! Posi 6 Lug Dana 60

03-19-2009, 07:27 PM	#12
coast2coast Registered User Join Date: Oct 2006 Location: Strafford Missouri Posts: 217	Re: rear end widths Anyone come up with confirmed numbers?

03-20-2009, 06:11 PM	#13
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths I haven't found the answer yet,,,,so I dunno. Frank __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

03-22-2009, 11:03 PM	#14
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: rear end widths Here are my numbers. I measured from wheel mount surface to wheel mount surface. 1970 GMC 1/2 ton truck long fleet with leaf springs 64-1/4" Front with 73-87 disc conversion 63-3/4" GM 12 Bolt 1970 62-3/8" Dana 60 1969 I have a 72 also, but the width will not be any narrower than the 70. You can see that the new disc conversion is only 1/2" wider than the original rear, or 1/4" each side. The D-60 is almost 2" narrower or 1" each side. Does this answer you question? __________________ '70 GMC C1500 LWB Power disc brakes. WooHoo! Posi 6 Lug Dana 60

03-23-2009, 08:22 AM	#15
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths Yes actually it does. Thank You! The front measurement was never a concern, but those rear end measurements were the numbers I was looking for. I need to be in the 57"-58" range to run a 12" wide wheel and still have it fit in the wheel well. Thanks again, Frank __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

03-23-2009, 08:33 AM	#16
72BlckButy Tot Roddin' Join Date: Apr 2005 Location: Mid-MO Posts: 24,461	Re: rear end widths This is a great thread... add this one to the file. __________________ -Nate 1969 CST SWB - Project Blank Slate (4.5/6" ECE Static Drop, 6-lug disc brake upgrade (manual), Billet Specialties Vintec 20x8.5 255/40 (F) 20x10 295/40 (R), 250 I-6) 1960 AMF Skylark - Tot Roddin' (Lowered with custom frame; soon to include custom push bar and interior) 2008 Silverado CrewCab 1LT (5.3L, 3:73, 4x4, LT1, Z-71, Towing Package)



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03-23-2009, 04:46 PM	#17
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: rear end widths No problem. I was researching rear widths as well as a number of other measurements for a swap I am preparing to do. I want it to go smoothly so I am measuring 10 times! __________________ '70 GMC C1500 LWB Power disc brakes. WooHoo! Posi 6 Lug Dana 60

03-23-2009, 04:57 PM	#18
sick69 Registered User Join Date: Sep 2006 Location: colorado springs colorado Posts: 737	Re: rear end widths That 70 12bolt,,,was it a coil spring rear end? Frank __________________ 70 chevy lwb c10 454/th400 and a 9" rearend suicide doors, marker light fuel fill, 4" cowl , mini tub

03-23-2009, 08:51 PM	#19
ERASER5 Registered User Join Date: Jun 2006 Location: Indiana Posts: 4,859	Re: rear end widths "1970 GMC 1/2 ton truck long fleet with leaf springs" I have not moved enough winter junk to get to the 72 Chevy with coils, but it should be the same as the 70. By the way, tell Dieselarmy to quit shooting at you! LOL __________________ '70 GMC C1500 LWB Power disc brakes. WooHoo! Posi 6 Lug Dana 60 Last edited by ERASER5; 03-23-2009 at 08:53 PM.

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