47-55.1 1/2 and 3/4 ton stock frames - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Nima · 12-06-2021, 02:04 AM

Hi:
Are these frames the same and their differences are only in their suspension/drivetrain or, the frames are different as well?
Thanks

51 3600 · 12-06-2021, 06:01 PM

Frames are the same to the rear of the cab. After that they are very different. 1/2 ton, 3100, keeps getting wider as it continues to the rear of the frame. 3/4 ton, 3600, frame stays the same width all the way to the rear. Frame rails are essentially parallel. I would assume all that is true for GMC but I can't say for sure.
Best to get a Factory Assembly Manual and you will have all the details on the frames.

Nima · 12-07-2021, 02:34 AM

Thank you.
It is interesting that 1/2 ton frame is wider than 3/4 ton.

**mr48chev** · 12-07-2021, 02:44 AM

This is the 3100 short bed 1/2 ton frame

Along with the 9-1/4 inch longer wheelbase for the 3/4 ton the rails run straight back from behind the cab rather than spreading out. Also a quick id is 1/2 ton springs are under the frame rails 3/4 ton springs are outsid the frame rails when you are eyeballing one somewhere. Also 3/4 tons barely have a kickup over the rear axle if any at all.

54 1/2 ton frames don't have much of a kickup over the rear axle as 54 and first gen 55 beds were down lower on the bed to make for deeper bed sides and a lower load platform.

GMC made a long wheelbase 1/2 ton frame and I have to think may have sold more of those than short bed trucks when they were new.

I've got one that my buddy gave me years ago so I can stretch my cab and still have a 1/2 ton frame.

You can see how the frame spreads out behind the crossmember that is normally under the back of the cab and ends up 40 something inches wide rather than just over 36.

Nima · 12-07-2021, 11:06 AM

Very informative. Thank you.
So, I assume the cab and front body panels are interchangeable between 1/2 and 3/4 tons but the bed panels can be different for 1st series?

**mr48chev** · 12-09-2021, 04:33 AM

The bed sides and wood strips are different lengths.

The stigma of having a long bed isn't what it was 48 years ago when I first bought my truck. Meaning that guys are building some nice long bed trucks rather than cutting the frame down to shorten it. Not everyone's cup of tea but no longer looked like a settled for as it was years ago but bed condition and running board condition come into play there too if you bought a long bed but really want a short bed. I know that sounds like a bunch of gibberish but If I had a long bed with real nice running boards and a real nice box I'd really consider keeping the long bed. That's money you can spend elsewhere on the build.

I'll dig in the garage tomorrow and see if I can figure out where I stuck my assembly manual and get the image of the 3/4 ton frame.

**Dan in Pasadena** · 12-17-2021, 12:14 AM

Quote:

Originally Posted by mr48chev

The stigma of having a long bed isn't what it was 48 years ago when I first bought my truck. Meaning that guys are building some nice long bed trucks rather than cutting the frame down to shorten it. Not everyone's cup of tea but no longer looked like a settled for as it was years ago but bed condition and running board condition come into play there too if you bought a long bed but really want a short bed.

A couple longbeds done nicely just to show you it can be done with VERY satisfying results. I'd have no trouble at all owning and being very proud of a longed that looked like these.

**mr48chev** · 12-17-2021, 03:13 AM

Long bed trucks are still the poor stepchild of the truck hobby in a lot of areas. The long bed 1/2 ton GMC trucks caught on with the Cali lowrider brigade right off but that may have been partially because you could buy a real nice unmolested long bed GMC for a lot less than you could buy a same condition short bed Chevy or GMC for. Plus the long bed gave you more room for the lowrider regalia such as the side mounts.

I'm stretching my cab 9-1/4 inches in the doors and running my short box on the long bed frame with long bed running boards. That's been the plan for that frame ever since my buddy gave it to me when he snagged the cab off it for a build he was doing. It hopefully will mess with a few minds. I need to get a tent stuck up and teach the cats to weld though.

Long beds to a lot of truck guys are like a 4-door sedan to car guys. Usually, it means you settled for second best because you couldn't find a two door you could afford. Younger guys seem to not give a rip about old cars having 4 doors because a lot of cars they have driven only came with 4 doors like my 98 BMW 528I If you were in high school and picked your date up in that car your date didn't care if it had 4 doors, that just meant her girlfriends could get in the back seat easier if you became a couple. Back in the mid 60's a gal might not have even got in the car if you showed up in a 4 door that looked like it might be your mommy's car. If you were out running around town in a long bed pickup it most guys thought, you were driving a work truck.

Nima · 12-17-2021, 11:02 AM

I actually don't mind long bed and also, I prefer a 4 door sedan to a 2 door.
The reason I asked about the frame differences was related to me working ion my 3/4 ton and I am toying with some ideas about front end and suspension modifications but since they are just ideas, I don't want to mess up my current project if it doesn't work out. It requires cutting and messing with the entire front section of the frame. Anway, I am keeping my eyes open to buy a spare frame and I wanted to know if I could use either 1/2 or 3/4 ton frames.

51 3600 · 12-19-2021, 03:07 PM

I bought my 3600 for the longer bed so I could use the truck as a truck doing my work flipping houses. Updating the drive train so I don't get run over on the highways going to and from work. Should I ever complete the transformation, going to and from a job will be just as fun as the work itself.

**Hcb3200** · 12-19-2021, 07:24 PM

One of the main reasons I like the 1956 model 3200 aka that year long bed is it really is what I term a "mid bed" they didn't go to the full 8 foot bed until 57 or 58.

So its not short. so I still have a bed with my truck box in it. But its not long to the eye as the full long beds are in the later years.

12-06-2021, 02:04 AM	#1
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	1/2 and 3/4 ton stock frames Hi: Are these frames the same and their differences are only in their suspension/drivetrain or, the frames are different as well? Thanks __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

12-06-2021, 06:01 PM	#2
51 3600 Registered User Join Date: May 2016 Location: Orange Park, FL Posts: 191	Re: 1/2 and 3/4 ton stock frames Frames are the same to the rear of the cab. After that they are very different. 1/2 ton, 3100, keeps getting wider as it continues to the rear of the frame. 3/4 ton, 3600, frame stays the same width all the way to the rear. Frame rails are essentially parallel. I would assume all that is true for GMC but I can't say for sure. Best to get a Factory Assembly Manual and you will have all the details on the frames. __________________ Al '51 3600, LS5.3, 4L60e, Danforth cross., Blazer front susp., Borg Warner 9 bolt 3.27 GR, Wrangler leafs

12-07-2021, 02:34 AM	#3
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Re: 1/2 and 3/4 ton stock frames Thank you. It is interesting that 1/2 ton frame is wider than 3/4 ton. __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

12-07-2021, 02:44 AM	#4
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,617	Re: 1/2 and 3/4 ton stock frames This is the 3100 short bed 1/2 ton frame Along with the 9-1/4 inch longer wheelbase for the 3/4 ton the rails run straight back from behind the cab rather than spreading out. Also a quick id is 1/2 ton springs are under the frame rails 3/4 ton springs are outsid the frame rails when you are eyeballing one somewhere. Also 3/4 tons barely have a kickup over the rear axle if any at all. 54 1/2 ton frames don't have much of a kickup over the rear axle as 54 and first gen 55 beds were down lower on the bed to make for deeper bed sides and a lower load platform. GMC made a long wheelbase 1/2 ton frame and I have to think may have sold more of those than short bed trucks when they were new. I've got one that my buddy gave me years ago so I can stretch my cab and still have a 1/2 ton frame. You can see how the frame spreads out behind the crossmember that is normally under the back of the cab and ends up 40 something inches wide rather than just over 36. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

12-07-2021, 11:06 AM	#5
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Re: 1/2 and 3/4 ton stock frames Very informative. Thank you. So, I assume the cab and front body panels are interchangeable between 1/2 and 3/4 tons but the bed panels can be different for 1st series? __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

12-09-2021, 04:33 AM	#6
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,617	Re: 1/2 and 3/4 ton stock frames The bed sides and wood strips are different lengths. The stigma of having a long bed isn't what it was 48 years ago when I first bought my truck. Meaning that guys are building some nice long bed trucks rather than cutting the frame down to shorten it. Not everyone's cup of tea but no longer looked like a settled for as it was years ago but bed condition and running board condition come into play there too if you bought a long bed but really want a short bed. I know that sounds like a bunch of gibberish but If I had a long bed with real nice running boards and a real nice box I'd really consider keeping the long bed. That's money you can spend elsewhere on the build. I'll dig in the garage tomorrow and see if I can figure out where I stuck my assembly manual and get the image of the 3/4 ton frame. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

12-17-2021, 03:13 AM	#8
mr48chev Registered User Join Date: Jul 2007 Location: Toppenish, WA Posts: 15,617	Re: 1/2 and 3/4 ton stock frames Long bed trucks are still the poor stepchild of the truck hobby in a lot of areas. The long bed 1/2 ton GMC trucks caught on with the Cali lowrider brigade right off but that may have been partially because you could buy a real nice unmolested long bed GMC for a lot less than you could buy a same condition short bed Chevy or GMC for. Plus the long bed gave you more room for the lowrider regalia such as the side mounts. I'm stretching my cab 9-1/4 inches in the doors and running my short box on the long bed frame with long bed running boards. That's been the plan for that frame ever since my buddy gave it to me when he snagged the cab off it for a build he was doing. It hopefully will mess with a few minds. I need to get a tent stuck up and teach the cats to weld though. Long beds to a lot of truck guys are like a 4-door sedan to car guys. Usually, it means you settled for second best because you couldn't find a two door you could afford. Younger guys seem to not give a rip about old cars having 4 doors because a lot of cars they have driven only came with 4 doors like my 98 BMW 528I If you were in high school and picked your date up in that car your date didn't care if it had 4 doors, that just meant her girlfriends could get in the back seat easier if you became a couple. Back in the mid 60's a gal might not have even got in the car if you showed up in a 4 door that looked like it might be your mommy's car. If you were out running around town in a long bed pickup it most guys thought, you were driving a work truck. __________________ Founding member of the too many projects, too little time and money club. My ongoing truck projects: 48 Chev 3100 that will run a 292 Six. 71 GMC 2500 that is getting a Cad 500 transplant. 77 C 30 dualie, 454, 4 speed with a 10 foot flatbed and hoist. It does the heavy work and hauls the projects around.

12-17-2021, 11:02 AM	#9
Nima Blue 67 Join Date: Apr 2004 Location: Western WA Posts: 1,179	Re: 1/2 and 3/4 ton stock frames I actually don't mind long bed and also, I prefer a 4 door sedan to a 2 door. The reason I asked about the frame differences was related to me working ion my 3/4 ton and I am toying with some ideas about front end and suspension modifications but since they are just ideas, I don't want to mess up my current project if it doesn't work out. It requires cutting and messing with the entire front section of the frame. Anway, I am keeping my eyes open to buy a spare frame and I wanted to know if I could use either 1/2 or 3/4 ton frames. __________________ 1953 GMC 3/4 ton: current project 1967 C20: 5.3 voretc with T5 conversion, 4 wheel 8 lug disc brake 1972 Nova: my 4 door sport sedan! 5.3 voretc + T5 conversion. drivable project, FUN!! 1979 Camaro Z28: 5.3 vortec conversion with build TH350: drivable project, Fun to drive 1992 Camaro RS convertible (Z28 clone): 5.3 conversion with build T5: on going project 2005 Silverado 2500, 4x4 Duramax, original owner

12-19-2021, 03:07 PM	#10
51 3600 Registered User Join Date: May 2016 Location: Orange Park, FL Posts: 191	Re: 1/2 and 3/4 ton stock frames I bought my 3600 for the longer bed so I could use the truck as a truck doing my work flipping houses. Updating the drive train so I don't get run over on the highways going to and from work. Should I ever complete the transformation, going to and from a job will be just as fun as the work itself. __________________ Al '51 3600, LS5.3, 4L60e, Danforth cross., Blazer front susp., Borg Warner 9 bolt 3.27 GR, Wrangler leafs

12-19-2021, 07:24 PM	#11
Hcb3200 Senior Member Join Date: Apr 2017 Location: Suwanee GA Posts: 252	Re: 1/2 and 3/4 ton stock frames One of the main reasons I like the 1956 model 3200 aka that year long bed is it really is what I term a "mid bed" they didn't go to the full 8 foot bed until 57 or 58. So its not short. so I still have a bed with my truck box in it. But its not long to the eye as the full long beds are in the later years.



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