[cj7jeep81]

I am beginning building up my '78 stepside truck. I am getting ready to tear down to the frame, swap the axles and engine, and build it back up. I am looking at buying a 3/4 ton donor truck to do this and got to thinking about swapping bodies instead of running gear. What it be worth it to shorten the frame and use it instead of my 1/2 ton frame?
If I did this, I imagine I would have to build new mounts for the bed, but am not sure.
Would there be value in doing it this way, or would it just be a major headache? I know I would end up with a stronger frame, but are there other benefits as well?

 

[azblazor]

Most of the information I have seen is that a 1/2 ton chevy frame is the same as a 3/4 ton chevy frame, for a given model line. As far as I can tell from the suburbans I have worked on that is true.

 

[cj7jeep81]

Thanks for the info :beer:. If that's the case, it wouldn't be worth it.

 

[chevyguybc]

my truck has a burb frame as far as i know.

what they did is just cut the middle down.. then re welded it and braced it heavily. its mint

 

[Ben427]

I would think it would be worth it id the 3/4 ton had the heavy chassis such as was available in the camper special or heavy duty package. I think theyre 8 inch channel and 5/16 or 3/8 thick. they are the best if your gonna really beef your rig. If you do shorten it, the two bolt holes behind the cab for box bolts are in the same spot whether its a shortbox or longbox, so leave them to locate the box so you can drill the rest of the holes accuratley.

 

[rodzzilla]

I have seen them shortened two ways. Either move your rear susp. hangers fwd and cut off the remaining part off the tail end. Or, cut the appropriate ammt from in front of the hangers and fish plate the pcs together. The truck done w/the fish plate has held up well. It has pulled fully loaded grain wagons on several occasions, and it is still in 1 piece.

 

[SOFA-KING BIG]

Here's another idea....
What about using a K5 frame?
It was shortened right from the factory!
Same stuff as 1/2 or 3/4 ton , And it has a 109 WB.
That's 10" shorter than a std pick-up.
Mounting it up was easy. And the mounts work, except...
The mount at the rear of the cab is lower for a blazer,
So you'd have to build a extension/ x-brace from the body mounts to the cab mounting holes.
Just another easy idea... :grinpimp:

 

[cj7jeep81]

Thanks for all the replies. I think I will just keep my 1/2 ton shortbed frame. Are there any benefits to using a 3/4 ton frame?

 

[Ben427]

Thanks for all the replies. I think I will just keep my 1/2 ton shortbed frame. Are there any benefits to using a 3/4 ton frame?

If you do get the 3/4 ton HD frame it will be less resistant to turning into a pretzel when you stick heavy axles and big meats on that beast and flex it out often.

 

[mj]

the 1/2t and 3/4t frames are identical on every one I have seen

I would not use a blazer frame, they have even more issues then the 1/2t and 3/4t

the only upgrade is a 1t frame

I used a late 80s c30 frame with the newest crossmebers and frame brackets I could find

 

[cdiamondc]

shortin a 1/2 T frame

chey frames differ from reg 1/2 to heavy (they came out with the Heavy 1/2 in 75 or 76) 1/2 ton. the Heavy halfs are the larger Channel frame , the same as the 3/4 tons! In about 82 they did away with the heavy stuff and the channel is the same as the blazers! I have a 77 3/4T that I'm making into a Short WB. I'd go take Pics, but there is about TWO plus feet of snow around it, so it will have to wait. I'm also puttin a 6.5TD with a 5spd. It will be my TOW bitch!! It will have a goose neck ball. I have a bumper pull, but for long distances I'm spoiled by a Gooseneck trailer. one other note, if you use a heavy half or 3/4 T chassis you will gain an extra 1inch in cab lift compared to the whimpy 1/2 chassis!

 

[mj]

I looked at a lot of frames when I was replacing mine
never saw a difference in any 1/2t or 3/4t frame rail

if you have images of a difference then post em up

 

[SOFA-KING BIG]

I think you found the answer to your question.
No advantages to using the 3/4 ton frame vs 1/2 ton.
The best way to see the actual differences between frames is to compare them first hand. Spend a little time in a boneyard, bring a tape measure & take notes.
If your serious and want to switch frames you have lots of options that will work, visually compare then ask some questions and use what 'you' think will work best.
Best of luck with your project!