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

BigChevMan · 10-10-2003, 02:07 PM

Ok...I have available to me a 69 c-20 long bed truck for very very very cheap. I have questions regarding the ability to change it to 1/2 ton suspension. I want to do a shortbed conversion. I guess my question would be what is different between the 1/2 ton and 3/4 ton. I was planning on just swapping in a whole crossmember & suspension from a 73-87 truck. Can I still do this? Please help. I don't want to lose this killer deal.

BigChevMan

**COBALT** · 10-10-2003, 05:08 PM

The frames are thicker, the trailing arms are reinforced with plates top and bottom (but can be used), coils are heavier, the lower ball joints are heavier (so the lower control arms are different), and of course the good ole 8 lug axle and spindles.

One of my projects is to convert my LWB 3/4 '69 C20 to 1/2 ton suspension (for either 5 or 6 lug pattern). I'm going to have to get a different rear-end (coil sprung), different spindles, different lower ball joints, different lower control arms.

There may be other issues too. The pitman arm, and idler might be different (you'll have to confirm that). For the most part you can use most of the rear suspension as is, but the axle is obviously a problem.

LeRoy · 10-13-2003, 06:24 AM

What about the rear 3/4 ton trailing arms. Seems that the u-bolt holes would be larger for the bigger diameter of the Dana 60, Corp. or whatever resides compared to a standard 12 bolt 1/2 ton rearend. I can check it out as I've got a set of both sitting around. Just a though. I do know that they are the same width at the attachment point on the crossmember

**COBALT** · 10-14-2003, 03:33 PM

From what I know the U-bolts are the same, but they would just sit deeper in the trailing arm due to the smaller axle. In other words I was under the impression that the trailing arms for 1/2 ton and 3/4 ton LWB were all the same, only the 3/4 ton arms were reinforced...

DoubleBit · 10-20-2003, 01:48 PM

First, why would you want to weaken your truck by converting 1/2t?
Second, would y'all be willing to chime in on my post about overloads? Maybe even sell yours to me if you are set on this course of modifications?

BigChevMan · 10-20-2003, 02:49 PM

Quote:

Originally posted by DoubleBit
First, why would you want to weaken your truck by converting 1/2t?
Second, would y'all be willing to chime in on my post about overloads? Maybe even sell yours to me if you are set on this course of modifications?

uh....because I want to? And because the only thing the truck is going to haul is a cooler and some lawn chairs.

crazy longhorn · 10-20-2003, 04:14 PM

My longhorn is converted to 1/2 ton suspension.....yes I have caught a little guff over it

you can bolt in the complete front crossmember from a 73 up truck, by egging a couple holes(I cant help on which ones). I run the factory crossmember, & top arms. The bottom arms are 71-72 1/2 ton pcs. A 75 c 10 gave up the spindles, rotors, & steer linkage....new ball joints, & tierod assys were installed. all of the brakes(master, lines , hoses , calipers & prop valve) are from the 75. The rear diff(12 bolt , & brakes) are also from the 75. I run a manual disc , due to vacumn issues on a "warm" 455 Olds that was in the truck at the time. The later booster can also be adapted if you need to.....its not a bolt in deal tho. Good luck,crazyL

DoubleBit · 10-20-2003, 04:29 PM

Well it IS still a free country and of course you can whatever you like with your truck. I did not mean to offend.
Good luck, and enjoy your truck.

Art

BigChevMan · 10-21-2003, 12:48 AM

Quote:

Originally posted by DoubleBit
Well it IS still a free country and of course you can whatever you like with your truck. I did not mean to offend.
Good luck, and enjoy your truck.

Art

None taken...Just was expressing my opinion on why I was choosing that route. Admittedly it would have been better to start with a 1/2 ton short bed to begin with...the price of 300 bucks for a running driving long bed 3/4 ton swayed me.

68 Suburban · 10-21-2003, 05:50 AM

As for the frame being thicker, from what I read in the 1968 data manual, that is false. Same material and thickness.

10-10-2003, 02:07 PM	#1
BigChevMan My Thoughts Exactly! Join Date: Jan 2003 Location: Ohio Posts: 140	3/4 ton question Ok...I have available to me a 69 c-20 long bed truck for very very very cheap. I have questions regarding the ability to change it to 1/2 ton suspension. I want to do a shortbed conversion. I guess my question would be what is different between the 1/2 ton and 3/4 ton. I was planning on just swapping in a whole crossmember & suspension from a 73-87 truck. Can I still do this? Please help. I don't want to lose this killer deal. BigChevMan

10-10-2003, 05:08 PM	#2
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	The frames are thicker, the trailing arms are reinforced with plates top and bottom (but can be used), coils are heavier, the lower ball joints are heavier (so the lower control arms are different), and of course the good ole 8 lug axle and spindles. One of my projects is to convert my LWB 3/4 '69 C20 to 1/2 ton suspension (for either 5 or 6 lug pattern). I'm going to have to get a different rear-end (coil sprung), different spindles, different lower ball joints, different lower control arms. There may be other issues too. The pitman arm, and idler might be different (you'll have to confirm that). For the most part you can use most of the rear suspension as is, but the axle is obviously a problem. __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

10-13-2003, 06:24 AM	#3
LeRoy Registered truck nut Join Date: Dec 1999 Location: Mt. Vernon, Washington, USA Posts: 1,584	What about the rear 3/4 ton trailing arms. Seems that the u-bolt holes would be larger for the bigger diameter of the Dana 60, Corp. or whatever resides compared to a standard 12 bolt 1/2 ton rearend. I can check it out as I've got a set of both sitting around. Just a though. I do know that they are the same width at the attachment point on the crossmember __________________ MOUNT VERNON, WASH. STATE Need a part? Just PM me

10-14-2003, 03:33 PM	#4
COBALT Senior Member Join Date: Sep 2001 Location: Seattle, WA, USA Posts: 5,817	From what I know the U-bolts are the same, but they would just sit deeper in the trailing arm due to the smaller axle. In other words I was under the impression that the trailing arms for 1/2 ton and 3/4 ton LWB were all the same, only the 3/4 ton arms were reinforced... __________________ '69 3/4 ton C20 2wd-350ci/TH400 '69 3/4 ton Custom 20 2wd-350ci/4sp Manual '99 2wd 5.7 Chevy Tahoe Seattle, WA.

10-20-2003, 01:48 PM	#5
DoubleBit Registered User Join Date: Nov 2002 Location: Auburn, CA Posts: 32	First, why would you want to weaken your truck by converting 1/2t? Second, would y'all be willing to chime in on my post about overloads? Maybe even sell yours to me if you are set on this course of modifications? __________________ Just remember, everything has two edges.

10-20-2003, 04:14 PM	#7
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,403	My longhorn is converted to 1/2 ton suspension.....yes I have caught a little guff over it you can bolt in the complete front crossmember from a 73 up truck, by egging a couple holes(I cant help on which ones). I run the factory crossmember, & top arms. The bottom arms are 71-72 1/2 ton pcs. A 75 c 10 gave up the spindles, rotors, & steer linkage....new ball joints, & tierod assys were installed. all of the brakes(master, lines , hoses , calipers & prop valve) are from the 75. The rear diff(12 bolt , & brakes) are also from the 75. I run a manual disc , due to vacumn issues on a "warm" 455 Olds that was in the truck at the time. The later booster can also be adapted if you need to.....its not a bolt in deal tho. Good luck,crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

10-20-2003, 04:29 PM	#8
DoubleBit Registered User Join Date: Nov 2002 Location: Auburn, CA Posts: 32	Well it IS still a free country and of course you can whatever you like with your truck. I did not mean to offend. Good luck, and enjoy your truck. Art __________________ Just remember, everything has two edges.

10-21-2003, 05:50 AM	#10
68 Suburban Registered User Join Date: Oct 2000 Location: From Chicago, Live in Phoenix, AZ Posts: 6,802	As for the frame being thicker, from what I read in the 1968 data manual, that is false. Same material and thickness. __________________ Just sitting here contemplating contemplation.



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