'76 to '87 rearend swap - The 1947 - Present Chevrolet & GMC Truck Message Board Network

lukecp · 09-23-2002, 03:41 PM

A buddy of mine has a '76 Chevy lwb C/10, with a 12-bolt rearend, and 3.08 gears. He has found a guy with a '87 lwb C/10 that has a 10-bolt rearend with 3.73 gears. They are going to try and trade the rearends straight across. Will the rearends bolt directly in place of each other? Are there any differences between the two in driveshaft length and U-joint sizes? Thanks for the help.

chevy68388 · 09-23-2002, 10:49 PM

i helped a guy put in a 14 bolt were a 10 bolt was went in no problem

gchemist · 09-24-2002, 07:14 AM

The 12 bolts and 10 bolts have different size yokes. The yokes are not interchangable. I know because I changed mine from a 10 bolt to a 12 bolt. I had to use a two sized U joint. I used NAPA part number 372 or 375. I can't remember for sure. I can check if you need the info.

73GMC · 09-24-2002, 09:50 PM

As long as the shock mounts, leaf mounts are the same, you should be ok. You will have to get the driveshaft from him or swap out yoke. Don't forget to disconnect brake lines.....

Good luck!

lukecp · 09-25-2002, 02:17 PM

The '87 is a 305/granny low 4spd truck, and the '76 is a 305/TH400 truck. Will the driveshafts interchange? Will the trucks have to be taken to a allingment shop after the changover is done?
Thanks for the help so far!

gchemist · 09-26-2002, 07:00 AM

I'm pretty sure the drive shafts are different lenths. Just swap the rear ends and buy the correct U joint for the rear. You won't need an alignment after the swap. I do recommend a front alignment at least every two to three years. Balancing the driveshafts would be a good idea too.

09-23-2002, 03:41 PM	#1
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	'76 to '87 rearend swap A buddy of mine has a '76 Chevy lwb C/10, with a 12-bolt rearend, and 3.08 gears. He has found a guy with a '87 lwb C/10 that has a 10-bolt rearend with 3.73 gears. They are going to try and trade the rearends straight across. Will the rearends bolt directly in place of each other? Are there any differences between the two in driveshaft length and U-joint sizes? Thanks for the help. __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

09-23-2002, 10:49 PM	#2
chevy68388 king $h!t Join Date: Jan 2002 Location: spring valley/ohio/usa Posts: 416	i helped a guy put in a 14 bolt were a 10 bolt was went in no problem __________________ j dawg the 86 allmost done 357/700r4/lifted 9/dana44 front ten bolt rear/3.73 gears/35s

09-24-2002, 07:14 AM	#3
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	The 12 bolts and 10 bolts have different size yokes. The yokes are not interchangable. I know because I changed mine from a 10 bolt to a 12 bolt. I had to use a two sized U joint. I used NAPA part number 372 or 375. I can't remember for sure. I can check if you need the info. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos

09-24-2002, 09:50 PM	#4
73GMC Proud American Join Date: Sep 2002 Location: Great State of Texas, USA Posts: 97	swap As long as the shock mounts, leaf mounts are the same, you should be ok. You will have to get the driveshaft from him or swap out yoke. Don't forget to disconnect brake lines..... Good luck!

09-25-2002, 02:17 PM	#5
lukecp Formerly yellow72custom Join Date: May 2001 Location: Austin, TX Posts: 7,531	The '87 is a 305/granny low 4spd truck, and the '76 is a 305/TH400 truck. Will the driveshafts interchange? Will the trucks have to be taken to a allingment shop after the changover is done? Thanks for the help so far! __________________ '72 Chevy C10 Mild 350/TH350/3.07. Ochre/White. Old high school ride. '70 GMC C2500 '62 327 4bbl/SM465/4.56-geared Dana 60. White/White. Project or parts truck. '97 Saturn SL DD. 1.9/5-speed. 40+ highway mpg

09-26-2002, 07:00 AM	#6
gchemist BAD BOW-Silverado XST Join Date: May 2000 Location: Senior Member from Austin, TX Posts: 6,431	I'm pretty sure the drive shafts are different lenths. Just swap the rear ends and buy the correct U joint for the rear. You won't need an alignment after the swap. I do recommend a front alignment at least every two to three years. Balancing the driveshafts would be a good idea too. __________________ Gerardo a.k.a. Mad Chemist Silverado XST videos



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