Frame Upgrade 1972 2WD C20 to C30

[1972C30]

I am looking for project advice in regards to a frame upgrade. Currently have a 1972 2WD C20 that needs to be upgraded to a 1 ton dual wheel configuration. Planning to utilize the 133" fleetside bed with wheel flares.

I have owned this truck for years and the C20 load capacity is a little light for my needs.

Should I locate a C30 2WD frame from an old C30 flatbed?

Any suggestions would be appreciated.

[67_C-30]

No, you want to keep the C-20 frame because it’s already the correct length. The C-30’s are either 133”, 157”, or longer wheelbase. Your C-20 is already the correct 127” wheelbase for a normal 8’ box. You add flares, you need a dually pickup rearend (or van based short bus rearend) to be wide enough to fit within stock wheelwells. Your ‘72 is nice because you already have discs. You just ‘71 - ‘87 dually rotors to run the correct wheels.

You can check out my build thread below. I would have had way less work in my truck if I had started with a C-20. I built one out of a C-30 the hard way, and then decided I needed diesel! 😂 If i can help you in any way, let me know!

[67_C-30]

I just re-read your post, and if you want to use the Longhorn bed then, yes you’d want a C-30 frame. If your bed is good though, I think you can get the towing capacity you want be upgraded your suspension and axles. You would obviously want to add leaf springs if it is a coil spring truck.

[1972C30]

Hi - I really appreciate the feedback. My current 8ft box has damage to the passenger side and will require a complete bedside. I currently have a rebuilt dual wheel axle with a disc brake conversion and the inner tires fit perfectly within the stock wheel openings. My C20 had leaf springs from the factory and my replacement 1 ton leafs will only require that I slide back the rear spring mounts about two inches on the C20 frame.

My concern was overall frame strength between a C20 and C30 frame. I was not sure if it was wise to locate a 133" C30 frame and utilize a Longhorn box? I was also not sure if the frame rails of a 133" C30 would even accommodate the mounting of a standard bed. It looks as if the frame rails on a C30 are lower near the cab. If this is the case, I imagine custom front pedestal mounts could be fabricated to mount the bed? Just not sure at this point.

The main issue for me?

1) Not sure if my existing C20 frame will handle the increased weight load?
2) If I move forward with a C30 frame - what should I be looking for in a C30 frame and how can I confirm that I am purchasing the correct frame for my project. I contacted several salvage yards about a C30 frame and they requested the following information:

4x2, 157" WB
4x2, 133" WB, Longhorn
4x2, 133" WB, exc. Longhorn

The question regarding Longhorn or except Longhorn did not make any sense. I was not aware that a Longhorn option existed on a 2WD C30??? I thought the longer box Longhorn only existed on 2WD C20's. I know the 157" frame would not be utilized, but two 133" C30 frame options? One with a Longhorn option???

Finally - If I made a decision to move forward with a C30 frame and determine what frame I am looking for - The next big issue is the Longhorn bed. I would have zero idea on locating one of these beds - Any ideas or a resource to locate one?

Thanks again!!!

[67_C-30]

Originally Posted by 1972C30

Hi - I really appreciate the feedback. My current 8ft box has damage to the passenger side and will require a complete bedside. I currently have a rebuilt dual wheel axle with a disc brake conversion and the inner tires fit perfectly within the stock wheel openings. My C20 had leaf springs from the factory and my replacement 1 ton leafs will only require that I slide back the rear spring mounts about two inches on the C20 frame.

My concern was overall frame strength between a C20 and C30 frame. I was not sure if it was wise to locate a 133" C30 frame and utilize a Longhorn box? I was also not sure if the frame rails of a 133" C30 would even accommodate the mounting of a standard bed. It looks as if the frame rails on a C30 are lower near the cab. If this is the case, I imagine custom front pedestal mounts could be fabricated to mount the bed? Just not sure at this point.

The main issue for me?

1) Not sure if my existing C20 frame will handle the increased weight load?
2) If I move forward with a C30 frame - what should I be looking for in a C30 frame and how can I confirm that I am purchasing the correct frame for my project. I contacted several salvage yards about a C30 frame and they requested the following information:

4x2, 157" WB
4x2, 133" WB, Longhorn
4x2, 133" WB, exc. Longhorn

The question regarding Longhorn or except Longhorn did not make any sense. I was not aware that a Longhorn option existed on a 2WD C30??? I thought the longer box Longhorn only existed on 2WD C20's. I know the 157" frame would not be utilized, but two 133" C30 frame options? One with a Longhorn option???

Finally - If I made a decision to move forward with a C30 frame and determine what frame I am looking for - The next big issue is the Longhorn bed. I would have zero idea on locating one of these beds - Any ideas or a resource to locate one?

Thanks again!!!

Longhorns came in C20’s and C30’s. The the C-30 Longhorns were still SRW. The frame even on the C20 is the bigger C30 frame. There was also a SRW C30 stepside with a 9” ft long bed on the 133” frame. As far as I know, the frame in the DRW C30, the Longhorns, and the 9!ft steeper’s were all the same. When I did my dually pickup, I cut the 133” down to 127” to run a normal bed and the bed mounted fine with the bed mounts off the same truck LWB I got my bed from.

As far as your frame’s capacity, how much are you looking to need? Also on your rearend, if they fit between your stock wheelhouses, they should stick way out past the bedside, correct?

[1972C30]

Hi - I have an old restored Jayco 11.5ft camper that is really heavy when loaded with camping stuff. It is not like these new campers. I also have my boat that I took regularly when the truck was operational. The 1 ton idea only came about because I was not happy with the stability - Even with new HD 3/4 ton springs and overloads it was not great. My friend moved my camper with a newer SRW Ford F350 and the camper was really heavy on his rig.

My rebuilt rear end is a Dana 70 and the front coils and leaf springs are also HD 1 ton springs. In regards to my comment about the (inner wheels) fitting perfectly in the wheel openings. The outer wheels are definitely outside the bed.

Was your 1 ton frame just a standard 133" non-Longhorn C30? Basically a true DRW style frame that utilized some kind of flat bed. I could certainly locate a 133" non-Longhorn C30 frame and cut the frame ends to re-utilize my original LWB C20 bed. That would be preferable since my bed is in decent shape.

I just need to make sure what 133" C30 frame I should be considering. BTW - Did you take any pictures of the frame you utilized when setting up your truck?

Thanks Again. I really appreciate feed back.

[1972C30]

Hello 67_C-30, I have a quick question regarding your leaf springs. You mentioned in a previous response that you utilized the front bed mounts from another truck and mounted the brackets to your C-30 frame. You also had to cut down the rear frame rails to utilize the standard Long Wheel Base bed.

If I am correct you also had to move your leaf spring mounts towards the cab in order to re-position the wheel for a 127" wheel base. Did the C-30 frame accommodate the spring mounts being relocated forward so you could utilize the standard 8ft bed.

Thanks

[67_C-30]

No, I had to cut 6” out of the frame behind the cab to shorten it and another 8” off the end of the frame. I couldn’t move the springs forward 6” because of the way the frame angles down. When you cut the 6” out of the frame, it practically makes the shape of the frame the same a normal LWB frame except it is thicker and the beam part of the cab is thicker/wider.

You can see in the this pic why you can just move the springs forward. This was the 133” frame before I cut it.

[67_C-30]

This is where it was sectioned and it is plated on both side with same diamond shape. You can see the bed mount I added above it.

[Motorfist]

I may be able to help?
I bought a 1970 c30 cab and chassis in Lehi a few years ago and put a longhorn bed on it. I sourced bed mounts from a forum member and bolted them to the frame. I had to cut a few inches off the end of the frame rails to accommodate the longhorn bed but otherwise it fit great.

I have a 67 c30 Drw cab and chassis sitting in my field. I’m using the cab hood and fenders on another project but the chassis and drivetrain will need a new home. I actually don’t remember the wheel base on this one but can measure tomorrow if you want. I’m located about 3.5 hours north of you.

You’ll be sad to know that I recycled an extra longhorn bed I had a few months ago. Had it listed for sale forever but no interest. They are around but you’ll have to drive to get one or have it shipped. Watch the parts board on this site. There is a member in Powell, WY that frequently has them for sale.

Feel free to pm me if you have questions.