converting to 5 lug - The 1947 - Present Chevrolet & GMC Truck Message Board Network

brutalpontiac · 11-07-2007, 05:03 PM

i know whats needed to convert the front end, but i havent had a chance to check out the rear end.
my question is do i have to replace the entire rear end? or can i just get a pair of 5 lug axles and brake assemblies and install them into the orignal 6 lug housing and carrier?

also while im thinking about it, i need a wiring harness for my 5.3l. any suggestions of where i might find one?

GMC3 · 11-07-2007, 05:30 PM

I took my axles to a machine shop and had them re drill the axles to 5 lug. and also the hub has to be machined to a smaller diameter for the 5 lug. I know a lot of people on here have swapped the axles out from a 5 lug truck, but i think you might need some spacers or something because of different width rears. some one will post what works

BarryB · 11-07-2007, 05:33 PM

No you can't just swap axles, reason being is that The earlier diffs, are narrower that the 71 72 diffs, I believe it is a difference of 1 1/2". So I would recommend just having the old axles redrilled for the 5 on 5 pattern. Heck of alot easier and cheaper in my opinion.

gotchevys? · 11-07-2007, 06:00 PM

I converted a 69 I used to have by having the rear axles redrilled and he also redrilled the drums.

Ackattack · 11-07-2007, 06:42 PM

I did 3 gen III wiring harnesses. I got 2 in a deal off of LS1tech and I found the other one at a salvage yard (the exact one I needed).

I then sold the 2 that I didn't need on ebay...so look there or craigslist.

**john** · 11-07-2007, 06:45 PM

If your truck is a 1970 chances are you can use 71-72 axles. Sometime during the 70 model they went to the wider housing. If you post your backing plate to backing plate measurement someone here can tell you if you have the wide housing.
Also Shifty has gathered alot of info on the 5.3 conversion and has alot of good stuff in this forum.

http://www.ls1tech.com/forums/showthread.php?t=370781

brutalpontiac · 11-07-2007, 09:30 PM

thanks alot guys.. ill get the measurement for the rear and go from there. as for the harness ill do some more searching and see what i come up with.

Ole Blue 68 · 11-07-2007, 11:57 PM

I used the rears off of a 75 to convert my 68 so it can be done. Reason I did was cause I got a good deal on them otherwise, I would have gotten my 6 lugs machined.

11-07-2007, 05:03 PM	#1
brutalpontiac Registered User Join Date: Oct 2007 Location: stephenville, tx Posts: 9	converting to 5 lug i know whats needed to convert the front end, but i havent had a chance to check out the rear end. my question is do i have to replace the entire rear end? or can i just get a pair of 5 lug axles and brake assemblies and install them into the orignal 6 lug housing and carrier? also while im thinking about it, i need a wiring harness for my 5.3l. any suggestions of where i might find one?

11-07-2007, 05:30 PM	#2
GMC3 Registered User Join Date: Aug 2002 Location: philadelphia Posts: 62	Re: converting to 5 lug I took my axles to a machine shop and had them re drill the axles to 5 lug. and also the hub has to be machined to a smaller diameter for the 5 lug. I know a lot of people on here have swapped the axles out from a 5 lug truck, but i think you might need some spacers or something because of different width rears. some one will post what works

11-07-2007, 05:33 PM	#3
BarryB Senior Member Join Date: Jul 2006 Location: Blountville, Tn. Posts: 3,904	Re: converting to 5 lug No you can't just swap axles, reason being is that The earlier diffs, are narrower that the 71 72 diffs, I believe it is a difference of 1 1/2". So I would recommend just having the old axles redrilled for the 5 on 5 pattern. Heck of alot easier and cheaper in my opinion. __________________ We could learn a lot from crayons... Some are sharp; some are pretty;and some are dull. Some have weird names; and all are different colours;but they all have to live in the same box. You may be only one person in the world, But you may also be the world to one person. * Some mistakes are too much fun to only make once. Two rules in life. 1. Never sweat the small stuff! 2. Everything is small stuff! Last edited by BarryB; 11-07-2007 at 05:33 PM.

11-07-2007, 06:00 PM	#4
gotchevys? Registered User Join Date: Dec 2006 Location: Virginia Posts: 118	Re: converting to 5 lug I converted a 69 I used to have by having the rear axles redrilled and he also redrilled the drums. __________________ www.fatdaddieshotrods.com

11-07-2007, 06:42 PM	#5
Ackattack Senior Member Join Date: Aug 2002 Location: Valley Center KS Posts: 3,525	Re: converting to 5 lug I did 3 gen III wiring harnesses. I got 2 in a deal off of LS1tech and I found the other one at a salvage yard (the exact one I needed). I then sold the 2 that I didn't need on ebay...so look there or craigslist. __________________ Project Bruiser: 68 Pro-Touring C-10 5.3L / 4L60E Project Ironhide: 97 GMC Crew Cab 4x4 Cummins SOLD: '69 GMC 1/2T SWB TBI'd: Project No Buck Assembly Manual Index Sign up Thread!!! Factory Service Manual Index

11-07-2007, 06:45 PM	#6
john member #16 Join Date: Dec 1999 Location: Yuba City Ca. Posts: 3,618	Re: converting to 5 lug If your truck is a 1970 chances are you can use 71-72 axles. Sometime during the 70 model they went to the wider housing. If you post your backing plate to backing plate measurement someone here can tell you if you have the wide housing. Also Shifty has gathered alot of info on the 5.3 conversion and has alot of good stuff in this forum. http://www.ls1tech.com/forums/showthread.php?t=370781 __________________ john http://67-72chevytrucks.com/vboard/showgroups.php board vendors http://www.flickr.com/photos/1745471...7602865984234/ Last edited by john; 11-07-2007 at 07:06 PM.

11-07-2007, 09:30 PM	#7
brutalpontiac Registered User Join Date: Oct 2007 Location: stephenville, tx Posts: 9	Re: converting to 5 lug thanks alot guys.. ill get the measurement for the rear and go from there. as for the harness ill do some more searching and see what i come up with.

11-07-2007, 11:57 PM	#8
Ole Blue 68 Registered User Join Date: Aug 2005 Location: Philly Posts: 1,140	Re: converting to 5 lug I used the rears off of a 75 to convert my 68 so it can be done. Reason I did was cause I got a good deal on them otherwise, I would have gotten my 6 lugs machined.



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