1970 Rear End Question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jmking9 · 10-08-2007, 01:53 AM

How do I tell if the rearend in my 70 is the wide or narrow one? I want to convert to 5 lugs but Im not 100% sure what axles i need. Is there A way to I.D. it? Can you get conversion axles for either one? Any help is appreciated.

72armyswbtruck · 10-08-2007, 07:05 AM

What do you mean by wide or narrow one, There is a difference between 67-72 rear ends and 73 and up rear ends. The 73 and up are longer (the axle half shafts).
On the rear end near the bell housing there should be some numbers, clean off the rear end and get those numbers and someone on here will chime in with the answers that you seek

70GMCer · 10-08-2007, 07:43 AM

In mid 1970 model year, they went to the longer rear. 57 1/2" compared to the older 56".

jmking9 · 10-08-2007, 10:36 AM

where do you measure from

67_C-30 · 10-08-2007, 10:40 AM

Backing plate to backing plate.

jmking9 · 10-15-2007, 07:42 PM

The only numbers I could find were on each side of the pumkin on the front of the axle. On the Drivers side it has "GM53" and on the passenger side "NF389683" are these th right ones to ID it. I measured it and I think its 57.5'' backing plate to backing plate. Are these the correct numbers, and if so, Can anyone ID it? Thanks

**lolife99** · 10-15-2007, 08:30 PM

I believe you should be able to use stock '71-'72 axles in your '70 housing since it's the wider version.

10-08-2007, 01:53 AM	#1
jmking9 Registered User Join Date: Sep 2006 Location: Riverton KS Posts: 832	1970 Rear End Question How do I tell if the rearend in my 70 is the wide or narrow one? I want to convert to 5 lugs but Im not 100% sure what axles i need. Is there A way to I.D. it? Can you get conversion axles for either one? Any help is appreciated. __________________ 1970 SWB Build

10-08-2007, 07:05 AM	#2
72armyswbtruck Registered User Join Date: Feb 2004 Location: Idaho Posts: 4,033	Re: 1970 Rear End Question What do you mean by wide or narrow one, There is a difference between 67-72 rear ends and 73 and up rear ends. The 73 and up are longer (the axle half shafts). On the rear end near the bell housing there should be some numbers, clean off the rear end and get those numbers and someone on here will chime in with the answers that you seek __________________ "Remember, They can Kill You, but they can't eat You, That's against the law!!!!!!!!!"

10-08-2007, 07:43 AM	#3
70GMCer Senior Member Join Date: Apr 2005 Location: Joppa, Maryland Posts: 4,408	Re: 1970 Rear End Question In mid 1970 model year, they went to the longer rear. 57 1/2" compared to the older 56". __________________ 1997 GMC Sierra Ext 1965 Mustang

10-08-2007, 10:36 AM	#4
jmking9 Registered User Join Date: Sep 2006 Location: Riverton KS Posts: 832	Re: 1970 Rear End Question where do you measure from __________________ 1970 SWB Build

10-08-2007, 10:40 AM	#5
67_C-30 I have a radical idea! Join Date: Jan 2005 Location: Sweet Home Alabama! Posts: 6,513	Re: 1970 Rear End Question Backing plate to backing plate. __________________ '67 C-30 Dually Pickup 6.2 Turbo Diesel, NP435 ‘72 C-10 SWB , 350 4bbl, TH350 '69 C-10 SWB , 250 L6, 3 OTT '69 GMC C3500, dump truck, 351 V6, NP435 '84 M1009 CUCV Military Blazer 67 C-30 Turbodiesel build thread http://67-72chevytrucks.com/vboard/s...d.php?t=254096 My trucks http://s226.photobucket.com/albums/d...ediafilter=all Member of the 1-Ton Club!

10-15-2007, 07:42 PM	#6
jmking9 Registered User Join Date: Sep 2006 Location: Riverton KS Posts: 832	Re: 1970 Rear End Question The only numbers I could find were on each side of the pumkin on the front of the axle. On the Drivers side it has "GM53" and on the passenger side "NF389683" are these th right ones to ID it. I measured it and I think its 57.5'' backing plate to backing plate. Are these the correct numbers, and if so, Can anyone ID it? Thanks __________________ 1970 SWB Build

10-15-2007, 08:30 PM	#7
lolife99 67-72 parts collector,… Join Date: Nov 2002 Location: Mid-MO Posts: 22,700	Re: 1970 Rear End Question I believe you should be able to use stock '71-'72 axles in your '70 housing since it's the wider version. __________________ Keith Convert to disc brakes. http://67-72chevytrucks.com/vboard/s...d.php?t=444823

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