Gearing help sought - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ole Greenie · 01-27-2011, 09:34 PM

I am looking to soon replace the 3.08 rear gear in my 70 CST short/step and am looking for loaner trucks for the swap. I would like to go to a 3.42 or 3.73 posi. What years and models should I be looking for if I have a 5 lug with coil springs and a panhard bar? Also which newer models would work...drum or disc but I would like to go to a disc set-up if I could with minimal alteration.

I have noticed alot of 4WD vehicles also have open diffs. so I am thinking that this search may be a long one. Thanks for any help you all could lend.

By the way, Ole Greenie is going into the paint shop Monday. Should take two weeks to complete.

Willys47 · 01-28-2011, 02:06 AM

don't forget that when you change the rear end to a differant ratio the speedometer needs to be calibrated as well.

Ole Greenie · 01-28-2011, 09:15 AM

Bump...

1low · 01-28-2011, 01:54 PM

you can use about any truck rear end but all the mounts will have to be cut off and re welded on the new rearend and the panard bar mount is cast into your housing so you will have to make a mount and prob get a longer or adjustable bar plus the factory posi are crap. you can get new gears and a good eton posi for about $800

01-27-2011, 09:34 PM	#1
Ole Greenie Registered User Join Date: Apr 2010 Location: Hagerstown, MD Posts: 246	Gearing help sought I am looking to soon replace the 3.08 rear gear in my 70 CST short/step and am looking for loaner trucks for the swap. I would like to go to a 3.42 or 3.73 posi. What years and models should I be looking for if I have a 5 lug with coil springs and a panhard bar? Also which newer models would work...drum or disc but I would like to go to a disc set-up if I could with minimal alteration. I have noticed alot of 4WD vehicles also have open diffs. so I am thinking that this search may be a long one. Thanks for any help you all could lend. By the way, Ole Greenie is going into the paint shop Monday. Should take two weeks to complete. __________________ John Paap Ole Greenie Hagerstown, MD My Mistress 70 CST Short/Step LS 5.3/4L65E New motor install Thread:http://67-72chevytrucks.com/vboard/s...d.php?t=667773 Last edited by Ole Greenie; 01-27-2011 at 09:36 PM. Reason: add-on

01-28-2011, 02:06 AM	#2
Willys47 Registered User Join Date: Dec 2007 Location: Nanaimo B.C. Posts: 604	Re: Gearing help sought don't forget that when you change the rear end to a differant ratio the speedometer needs to be calibrated as well. __________________ I was hooked on these trucks since 1982 when I drove my budys fathers 1968 Custum GMC 396 automatic dana 60 rear with a power lock diff what a ride more fun then we will we can ever tell!!

01-28-2011, 09:15 AM	#3
Ole Greenie Registered User Join Date: Apr 2010 Location: Hagerstown, MD Posts: 246	Re: Gearing help sought Bump... __________________ John Paap Ole Greenie Hagerstown, MD My Mistress 70 CST Short/Step LS 5.3/4L65E New motor install Thread:http://67-72chevytrucks.com/vboard/s...d.php?t=667773

01-28-2011, 01:54 PM	#4
1low Registered User Join Date: Feb 2010 Location: Moyie Springs ID. Posts: 160	Re: Gearing help sought you can use about any truck rear end but all the mounts will have to be cut off and re welded on the new rearend and the panard bar mount is cast into your housing so you will have to make a mount and prob get a longer or adjustable bar plus the factory posi are crap. you can get new gears and a good eton posi for about $800



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