3/4 ton questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

mikecaddy500 · 01-20-2018, 06:46 PM

I've heard that 1/2 ton trucks can swap in 73-87 front "A" arms for better geometry. Does this work for 3/4 ton trucks? I don't want to lower it as I plan on a camper and a car trailer. 72 custom camper. Also looking for posi traction for the eaton rear end.

Mike C · 01-20-2018, 09:34 PM

I swapped in steering knuckles and discs from a 73 and up into my 70 GMC 2500. Had to change balljoints and use newer tire rod ends. But you can do the complete swap. Not sure how much geometry is changed though?

No limited slip available. Only traction device for the Eaton is the Maximum Traction locking diff. (Detroit) You can use one from a 14 bolt if you use the later 14 bolt axles.

**Steeveedee** · 01-21-2018, 12:00 AM

If I understand correctly, '68-'72 A-body cars can use the '73-'87 upper control arms for improved handling, which requires a bunch of other modifications (different ball joints, shocks, etc). Are you going to be road racing your truck? Otherwise, just leave it as it is, IMO. My truck has been pulling a trailer since it was new with the factory design, and steers just fine.

cheyenne shortstep · 01-23-2018, 02:48 AM

73 -87 C/10 lower arms are longer than 72 and earlier, hence the geometry change. C/20 arms remain basically the same so no real change to geometry.

KevDiesel · 01-23-2018, 12:55 PM

http://67-72chevytrucks.com/vboard/s...d.php?t=444823

The above thread is a great resource for you. The C20 upper control arms and shafts are the same among many years. Check it out.

01-20-2018, 06:46 PM	#1
mikecaddy500 Registered User Join Date: Jan 2015 Location: howard city mi Posts: 83	3/4 ton questions I've heard that 1/2 ton trucks can swap in 73-87 front "A" arms for better geometry. Does this work for 3/4 ton trucks? I don't want to lower it as I plan on a camper and a car trailer. 72 custom camper. Also looking for posi traction for the eaton rear end.

01-20-2018, 09:34 PM	#2
Mike C Registered User Join Date: Dec 1999 Location: Austin, TX, USA Posts: 7,709	Re: 3/4 ton questions I swapped in steering knuckles and discs from a 73 and up into my 70 GMC 2500. Had to change balljoints and use newer tire rod ends. But you can do the complete swap. Not sure how much geometry is changed though? No limited slip available. Only traction device for the Eaton is the Maximum Traction locking diff. (Detroit) You can use one from a 14 bolt if you use the later 14 bolt axles. __________________ 44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax

01-21-2018, 12:00 AM	#3
Steeveedee Who Changed This? Join Date: Jan 2013 Location: Simi Valley, CA Posts: 10,081	Re: 3/4 ton questions If I understand correctly, '68-'72 A-body cars can use the '73-'87 upper control arms for improved handling, which requires a bunch of other modifications (different ball joints, shocks, etc). Are you going to be road racing your truck? Otherwise, just leave it as it is, IMO. My truck has been pulling a trailer since it was new with the factory design, and steers just fine. __________________ ~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA

01-23-2018, 02:48 AM	#4
cheyenne shortstep Registered User Join Date: Jul 2010 Location: Vista Ca. Posts: 2,405	Re: 3/4 ton questions 73 -87 C/10 lower arms are longer than 72 and earlier, hence the geometry change. C/20 arms remain basically the same so no real change to geometry.

01-23-2018, 12:55 PM	#5
KevDiesel Registered User Join Date: May 2016 Location: SF Bay Area, California Posts: 15	Re: 3/4 ton questions http://67-72chevytrucks.com/vboard/s...d.php?t=444823 The above thread is a great resource for you. The C20 upper control arms and shafts are the same among many years. Check it out.



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