roxxx

I will be getting mine back tomorrow hopefully , I will be doing just that . I hope they are the same just cuz its such a good deal

PapeCAT

From Mysteryman:

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

simplysmn

It's going to take me a little while I am in a different town then the crewcab but next time I go up there I will get pic's

roxxx

thank you Pape I hust found this last night Very good info

Richie O

I had actually posted that same write up on another site but it goes against what my factory service book says. I wonder which is right. I have talked to Terry before and I know he knows these trucks well. Just makes me wonder.

78Wagon

My 78 club cab shortbox has the 7.5 inch deep center section. It was just a 4wd 1/2 ton originally and appears to be the same thickness as my 90 with the 6 inch frame.Both frames look to be about the same deepth every where else.

CaptainChrysler

I will have to put a tape to it, but I'm pretty sure the '89 has the 8" frame. It looks just like my '93's frame.

E.Roy

Hey guys,

I'm thinking of picking up another 1st gen Cummins, an early 91 reg cab non-intercooled D350 DRW.

My question is what frame should the early 91 dually have? Or what does your 91 dually have?

(It's 5 hours away hence my question)

E.Roy

Heads up on thin frames on the D100 2wd trucks.
Just picked up a 1988 D100 RCLB, the frame (6") is only 1/8" thick (edit .156")...well thin! Not Cummins or offroad friendly. It also has 1/2" rear leaf spring bolts, and rear hangers are thinner as well

Edit: Ramchargers have same .156" thick frame as D100. Probably fine given the short 106" RC wheelbase

I currently have a 1990 W150 4x4 Club cab long bed, that has the ~7.25" frame with wider flanges as well, and it is .220" thick. This is clearly because of the long wheelbase.

Meanwhile my trusty 1991.5 W250 Cummins RCLB has the 6" frame .194" thick, and the flanges aren't as wide as the 90 w150 above.

u2slow

My 89-90 diesels have all had 6" tall frames. US production - 1st vin digit "1".

The 91.5 (IC) and '92 I wrecked out, and both '93's have 8" tall frames. Mexico production - 1st vin digit "3".

HTH.

E.Roy

Thank you for the input. Were any of the 89-90 D350s?

I just bought a wrecked 1992 D250 Cummins Reg cab with 8" frame, 1st vin digit 1

And below indicates the 91.0 D350 truck I am interested is likely an 8" frame, just found a picture of an early 91.0 D350 non-IC DRW (not C&C) and it has the 8" frame, 1st vin digit 1, 1B7ME3680MS234151

u2slow

No, all D250 with the 4k# suspension.

Afaik, 250 and 350 pickups use the same frames in a given year from the same plant.

E.Roy

Has anyone confirmed any 1 ton, Cab Chassis or '92-93' frames came 1/4" thick material? I don't know where I heard some were 1/4" thick, but it got in my head somehow
I just junked out a wrecked 1992 D250 Cummins RCLB with 8" frame and it was 3/16" thick

cougar

I have no information indicating any differences. However many chassis cab units were modified by aftermarket venders for designated tasks such as stretched box or camper use.

u2slow

This link lists the frame dimensions used in '75. The trend seems to be thicker steel for the longer wheelbases.

https://www.ramchargercentral.com/th...erences.39593/

I wish I could find similar data for 92-93. The 8" frames I have are still 7" under the cab... then from the upward slope and to the leaf spring hanger they measure 8". I'll see if I can get a thickness measurement off a not-so-rusty spot. (I have 131" and 149" WBs)