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| | | | Joined: May 2019 Posts: 17 New Guy | | New Guy Joined: May 2019 Posts: 17 | Hi:
I have two questions if you can help me with the answers:
1- Does the 1/2 ton suspension bolts up to 3/4 ton or is there any dimensional differences? For example does the leaf springs are the same size/length and their differences are in the load ratio only?
2- Besides the wheel base, is there any structural differences between 1/2 ton and 3/4 ton frames? is 3/4 ton thicker, larger…...?
Thanks
1953 GMC 150: new member 1967 Chevy C20, 4 wheel 8 lug disc, 350 engine with Fitech carb (in progress) , T5 1972 Chevy Nova, 4 door sport sedan in the making  1979 Chevy Camaro Z28, 5,3 Vortec and TH350, 4 wheel disc and Hydroboost; Just about becoming summer daily driver
| | | | | Joined: May 2015 Posts: 11,150 Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums | | Housekeeping (Moderator) Making a Stovebolt Bed & Paint and Body Shop Forums Joined: May 2015 Posts: 11,150 | For AD (47-54) trucks, according to the FAM, distance between front spring eyes on the frame are the same on 1/2 and 3/4 ton, but the rear springs are actually longer on the 1/2 ton (~52") than the 3/4 ton (~44"), and according to the GM specs, the 3/4 ton frame is deeper (vertical dimension) and also thicker (3/16" versus 9/64"). The 3/4 ton rear springs are wider (2") than the 1/2 ton rear springs (1-3/4").
Kevin 1951 Chevy 3100 work truckFollow this saga in Project JournalPhotos 1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car) Busting rust since the mid-60's If you're smart enough to take it apart, you darn well better be smart enough to put it back together. | | | | | Joined: May 2005 Posts: 8,878 . | | . Joined: May 2005 Posts: 8,878 | In addition to the above. For 48-54 (you didn’t specify year?)
You can easily remove and replace 1/2 ton and 3/4 ton front axles with each other because the springs are the same width and spacing. The 3/4 ton would have stiffer springs, you could also swap front springs between them if desired.
The rear part of the frame (behind cab) is vastly different between 1/2 ton and any larger truck.
1/2 ton kind of flares out wider and wider as the frame goes back.
3/4 ton and larger has parallel frame from the cab back at about 36” outside to outside. | | | | | Joined: May 2019 Posts: 17 New Guy | | New Guy Joined: May 2019 Posts: 17 | Thank you very much for the detail. I am sorry, I didn't mention the model and year since it was in my signature, 1953 GMC 3/4 ton. I guess the next question would be if there is a difference between Chevy and GMC frames.
So, if the frame is different behind the cad, the bed panels from 1/2 will not fit 3/4 ton, is this correct?
I have a 3/4 ton than I plan to keep the 8 lug driving gears but I don't mind the 1/2 ton softer ride.
Last edited by Self; 06/13/2019 4:09 PM.
1953 GMC 150: new member 1967 Chevy C20, 4 wheel 8 lug disc, 350 engine with Fitech carb (in progress) , T5 1972 Chevy Nova, 4 door sport sedan in the making 1979 Chevy Camaro Z28, 5,3 Vortec and TH350, 4 wheel disc and Hydroboost; Just about becoming summer daily driver
| | | | | Joined: Feb 2004 Posts: 29,870 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,870 | If you're not planning on doing "real truck" stuff you can soften the ride by removing a few leaves from the 3/4 ton springs. That would be a lot simpler than trying to do a swap of major components like complete spring packs, etc. Leave the main leaf in place for mounting purposes, and remove a few of the shorter, stiffer upper leaves. You can also soften the ride somewhat by using thin Teflon strips between the spring leaves to let them slip past each other more easily. Some of the "resto-modded" Cowboy Cadillacs never see a load heavier than an iced-down Yeti cooler on the way to a tailgate party- - - - -heavily padded to avoid putting scratches in the glossy-varnished Mahogany bed wood with chromed hold-down strips.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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| | | | | Joined: Jun 2011 Posts: 5,096 Crusing in the Passing Lane | | Crusing in the Passing Lane Joined: Jun 2011 Posts: 5,096 | And fuel fillers in the middle of the bed, making sure they will never carry anything in the bed.
Ed
'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.
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