chevy frame strength?

[Forrest Nearing]

I'm wanting to convert an early-to-mid 70's suburban over to Cummins power...



drivetrain plans are:



NV4500, NP205, D60 front, D80 rear.



is there a difference in the frame in those years or was it just the suspension and drivetrain components?



finding a clean 3/4 ton suburban w/ a manual transmission is tough... seen a few... but if the frame on the 1/2 tons is the same, I can look for them too!



thanks,



Forrest

 

[McCRam]

From 73- 87,There were minor changes in the frame, although I don't think there was anything that would make one particular frame stronger than another. Although 72 and earlier, the frames are considered much weaker. I think you are right that the 1/2 aand 3/4 ton frames are the same.



A good website for chevys www.chevytalk.com

 

[Forrest Nearing]

thanks for the info... I thought I'd heard there was a year break where the 1/2 ton frames became lighter/weaker than the 3/4 tons, but I couldn't remember what year it was... for some reason I thought it was around 77 or so, but I could be WAY off...



I like the square bodied trucks w/ the round headlights... would like something fairly early for smog reasons... maybe 73-74?



Forrest

 

[McCRam]

The one thing I can tell you for a fact is I parted out a 77 3/4 ton to fix my 84 1/2 ton truck after I smashed it, and I couldn't find any significant differences. Even parts like the spring shackles were the same. Good luck on your project. When my dodge wears out, I plan on throwin the cummins in a late 70s crew cab.

 

[DPinkston]

thanks for the info...

I like the square bodied trucks w/ the round headlights... would like something fairly early for smog reasons... maybe 73-74?

Forrest

Good Luck. I thought all the 73-74 Chevy's had rusted to the ground 25 years ago. We had 2 of them and in no time we could watch the road whiz by beneath our feet. Very poor quality materials used in the bodies.

Danny

 

[Forrest Nearing]

hmm... maybe I'll use an '89 and just do a VIN swap

 

[dcamilleri]

Mine was originally a 1/2 ton and the frame is lighter than the 3/4 ton of the same year about 3/16 compared to 1/4". All of the same holes are there however, because I changed mine over to use 56 inch one ton rear springs and just had to move the hangers to the other set of holes. No real issues with the frame except if I load my trailer real tongue heavy I can notice the frame moves away slightly from the body.

 

[Forrest Nearing]

I heard there was a year break where the 3/4 and 1/2 ton frames were the same... thought it was in the late 70's... after that, the 1/2 tons were lighter. I definately want the heavier frame!!!

 

[dcamilleri]

Can't tell you for sure what year the break was, but from 1983 up the 3/4 tons definetely had a heavier frame.

 

[FTwardoch]

I'm wanting to convert an early-to-mid 70's suburban over to Cummins power...



drivetrain plans are:



NV4500, NP205, D60 front, D80 rear.



is there a difference in the frame in those years or was it just the suspension and drivetrain components?



finding a clean 3/4 ton suburban w/ a manual transmission is tough... seen a few... but if the frame on the 1/2 tons is the same, I can look for them too!



thanks,



Forrest

Go to www.coloradok5.com for the BEST Chevy site on the web... ... ... ..... frame was weak around the steering box, there are gusseting kits (weld on) available as well as steering box braces (from Off Road Design) that solved the problem. The 14BFF rearend is plenty strong enough for the Cummins, no need to swap to the D80, and Detroit Lockers are literally a do it yourself project and only cost $350. If you need the how to install a Detroit article, let me know via PM and I'll get the link for you.