The Stovebolt Site Forums The Parking Lot Big Bolts frame swap

I have been given a 52 or 53 Gmc Big Boldt. I am waiting for it's delivery so I can get better pics and figure out exactly what it is . But it is the regular Advance Design cab with a fifth wheel. the Frame has been hacked real good so I am going to put it on another frame. A couple of options would be a 63 to 65 1 ton that happen to have a 292 in it. But I will be going with a 261. Another option is a 1960 C-60. Which I think has a 261. The wasps ran me off before I could get a better look. Anyone try swaps such as these or any comments? Thanks.

Welcome to the Stovebolt Jesse!

GMC's with the standard cab had three different fender/grill configurations. I don't know the breakdowns, but basically 1-ton and smaller trucks are the same as a pickup, the next level is the same as a Chevy 1-1/2 or 2-ton, and the 3-ton (450 series I think) has something even bigger. Then there are even bigger trucks that have a slightly different cab in addition to different fenders, hood and grill.

The significance of the fender size is that the track width on a 60's truck is enough wider than the '52 or '53 that unless you have the biggest fenders, keeping the wheels under the fenders will complicate the swap.

What are you going to do with the truck? Unless you intend to haul heavy loads I'd stay away from the added weight of the C-60. Not only does it weigh more, but brake and suspension parts are likely harder to find. Also your intended use might suggest other ideas.

The '63 to '65 frame will have a coil spring IFS that can easily be swapped with a '71 to '87 that would give you disk brakes. That might be another consideration. Mounting the 261 in the later frame may require fabricating some mounts, but if you are contemplating a frame swap you must already be comfortable fabricating mounts.

Another thought would be to look for an earlier frame. They are not that hard to come by in my area.

The truck is at least a 2-ton. So it has the "big" fenders". It's not the "semi" 450 style. I wasn't keen on stealing the frame on the c-60, because it looked like a decent truck still. But I will steal the 261. So the 1-ton mid sixties frame sounds like the one to go with. I don't plan on hauling huge loads with it. Pull my boat, haul some stuff to the gas and steam show. Thanks for the tips.

Welcome!

So far I think you may be better off finding an original replacement frame for what you plan to do.

If you do end up swapping frames take a bunch of measurements before you completely decide it is the right thing to do. As Steve points out, the track width and fitting tires under the fenders will be the big challenge with a newer frame.

Personally I think the original style frame is the best choice. The cab and front sheet metal already fits and looks good on it. In your case the engine you have in mind will be a good fit. And with that engine and your planned use the stock axles, gears, and brakes should suit your needs.

Then if you want better axles, brakes, and gear choices you can still use the old frame, and it may be simpler to swap axles like I have done, than it is to swap an entire frame and drivetrain. But either one is still a lot of work.

Grigg

I totally agree. And I will be keeping my eyes peeled. Two things play into this tho. Finding a frame nearby, and cost. I am lucky in that that our neighbors who have a junkyard are setting us up with Free stuff. They did have a 50'ish 1 ton but that's gone now. After the Iola car show I should be able to post some pics of what I have. Thanks.

60's one tons have those cussed low cab heigth and high hump frame which would give a larger cab like yours that pervebial monkey with a football appeareance. I'd go with an original also.

Hey Jesse,
I have a 54 Chevy 1 1/2 ton, 4400, frame that's in really good condition just laying around here. If you're ever anywhere near central Iowa (Cedar Rapids area), stop in and have a look,
Scott

Thanks for the offer but I don't think I will be that way anytime soon. I think I need to wait till the truck arrives and really see what I have to work with. Perhaps the frame is not as bad as I thought. Here are some low quality cell pics I took of the truck and the motor in the C-60. http://www.flickr.com/photos/28409797@N04/

If the frame behind the cab is not to your liking, and you have access to a
c60 frame, you can probably cut it and splice a piece of the C60 frame onto it. If you fabricate a glove for inside of the frame and then V out the splice and weld and grind it, it will look nice and be strong. If you are going to subject it to heavy loads, a cross member at the splice and a fish plate over it wouldn't hurt anything. Frames are stretched like this all the time

Normal frame width for new trucks is about or exactly 34" outside.
The frame width on an AD truck is 36" outside.

So you can't go to new with the donor frame. How long after AD trucks, if any, did frames stay 36"?

Grigg

Frames have been 34" for many years, probably since the mid 50's or 60's. However, frame width depends on the length of the cross member. The first frame stretch I can remember doing was on a 1956 GMC 550. I added a drag axle and used piece of frame from an R190 International. We now use what is referred to as tanker spec cross members to accommodate a glove because a cross member has to be shortened 3/4" to accommodate a 3/8 glove. 5 piece are a c channel with 2 gussets at each end. 7 piece have another gusset over the top.

Grigg,

Starting with 1955 Second Series "Task Force" trucks the frame width went to 34".

Mike B

Then Mike just answered your question about using the back half of a newer truck frame.
Unless you make a funny looking transition from 36" down to 34" it won't work.

Although I suppose you could add the new frame about mid way under the cab, where the frame tapers in and at some point in that taper it is 34". You would have to adapt the rear cab mounts.

Probably simpler and less work and time to find a decent used frame for the model truck you already have....

Grigg

The width is in the cross members, not in the frame itself. I would think you would want to keep your 36" frame or you would have all kinds of problems in the front end. However, you could add frame channels and either use your 36" cross members, shim the 34 " cross members an inch on each end, or fabricate your own and bolt it together. Flange bolts worked on class 8 trucks for 40 years until they went to Huck bolts in the mid 90's.