What is different on the suspension and frame between the three? I know the springs and the axles are different. Is the frame made from a thicker steel with the 3/4 and 1 tons?

 

This was stolen from MYSTERYMAN on TDR.

The frames from 72 threw 93 are basically the same at a glance but quite different if you look closely..

The 8" (some were 7.5") frame was used on all the cab/chassis models. It was also used on all the 1 ton pickups and select 3/4 ton trucks..

Most of the 3/4 ton and all of the half ton's used the smaller 6" center frame.

The 1st gen diesels 89,90,91.0 250, 3/4 ton used used the 6" frame but it was a bit heavier than the earlier gas version. You could order the 8" frame
if desired but most were called single wheel 350's rather than 250's

89,90,91.0 350, 1 tons used the taller 7.5 " to 8" frame. The 8" was a bit heavier than the earlier gas version..

In 91.5 the 8" frame was updated and is heavier than all the rest that came before it... This is hard to see with the naked eye. But quite obvious on the blueprints. It was updated and the 6" frame was discontinued due to breakage problems... in conclusion.....
All 91.5, 92 and 93's 250's and 350 diesels used the SAME frame ...

The exceptions.....2wd verses 4wd....The frames are the same except for the front cross member's and spring hangers....

Converting a 2wd frame to a 4wd frame is rather easy assuming that you have the 4wd engine cross member and 4 spring hangers...


Converting a 4wd frame to a 2wd frame is a whole lot of work !!!!! You have
to change the front cross member and the engine cross member.. Weld in the motor mounts. Mount the upper control arm brackets.... None of the holes will be pre drilled for you. You will have to drill them all yourself.. The tolerance for these holes is .125 (1/8") on center .. If you miss the mark you may never get it to take a front end alignment or track properly...
I would not recommend doing a 4wd to 2wd frame conversion to a novice
or back yard mechanic..

One last note..... If you need to replace an 89,90 or 91.0 6" 250 diesel frame. And if you can not locate a diesel frame.. You can use an early 7.5" 300 gas frame.. All the holes will line up for the most part...

Be sure to measure the wheelbase of the doner frame you buy...
Trucks that were sold as "cab/chassis" have longer frames than Pickup trucks.

And dually rear axles out of "cab/chassis" trucks are NARROWER than the dually rears out of pickup trucks..

Dually rears out of "cab/chassis" CAN be used in most cases in single wheel pickup trucks.. You may need to change the gears to get highway speeds with the diesel.. 3.55 to 1 ratio is the best choice for all around use when using stock size tires.

I hope this answers all the frame questions

 

Thanks, that is exactly what I was looking to know.

How much weight capacity do you think could be added to a 1/2 ton by boxing the frame. Truck is an '85 so I have the small 6" frame.

 

wontacceptthis: Great info. You should paste that in the do it yourself sticky so others can find it easily.

 

JGC403 - that would do nothing without also changing suspension. Also, your truck can never legally change capacity. The weight on the door is your legal gross, no matter what.

SEAL - thanks. Will do.

 

ya. you can never change the legal capacity but you can always make it look better when you are loaded to the maximum capacity. my truck has 2 extra leafs per side and i would have to put more than maximum weight capacity to make it sit the same as a stock truck.

 

Alright I see thanks.

 

I have a 74 1 ton 4 x 4 power wagon with a rusted out frame. I bought a 2 wheel drive 1 ton camper special. I was going to cut the frame at the cab and put the good frame on the 4 x 4 A member has mentioned that they are the same frames and I can just change out the spring hangars and x member. Does anyone have any experience doing this. Any help would be appreciated.