The Stovebolt Site Forums The Shop Area The HiPo Shop 53 3/4 ton GMC chassis question

Ok so after carefully going over the chassis I have I have decided that I want to sell it to someone with more knowledge/skill that can actually do the work to it that it needs done. As I do not have those kinds of skills. I want my truck to be as modern as possible so I was wondering if there is a truck a truck Chassis out there that I could swap to that can take a V8 already and is already set up with disk brakes ect? I understand this is not what most would do but I am just trying to get her running and usable as this is my only truck, so until she is done I have no ride.

What was the problem(s) that led you to this decision?

If you don't have a way to work on or fix the original frame then a complete or partial frame swap is probably not for you.

The simplest way to get a truck on the road is almost always in it's original form, or close to it.

What do you want to do with the truck?

Grigg

Answer Grigg's question about what you want to do with the truck. It does help a lot to know what someone is trying to acomplish.

You might consider one of the S-10 kits that take much of the fabricatoin out of using an S-10 frame. You'll still have a lot of work to do though...

I'm courious, whats wrong with the frame? No matter which way you go, S-10, subframe, Must II, your going to have plenty of work and none of it easy. I know that resto parts are geared for 1/2 tons, so maybe thats why your thinking this way? Hang in there, some stovebolter will come along that has been there done that.

The current frame looks like someone took, no I am certain someone took a torch and blew holes in the side of the frame every 6 inches for the custom bed they made for it. Since I am not keeping the bed he made that also means I'm not keeping the bed supports he made which leaves the frame with about 20 or so 1 inch holes that were not properly painted or anything and are currently covered in surface rust. Weather or not that will cause a problem for the truck frame I am not sure, what I do know is that it will irritate me every time I think about it even if I can not see them.

As far as what I want to do with the truck, I want to replace the engine, Looking at several options a 292, the 4.2L out of a trailblazer, or I was possibly thinking of trying to find an older Inline 6 Diesel I can use. I am not able to find much info on my truck. I know it either had the 248 or the 228 in it but I would much prefer a diesel engine. As far as the transmission, Id like to upgrade to an automatic maybe an Allison 1000, or a 700R4, as I have a bumb leg and cant drive a stick. all of the body work, I am hoping to keep original, no lifts, or lowering here, just want to re-power the truck with something a little more modern, and a little more environmentally friendly so that the wonderful state of CA will leave me alone!

I'd consider a replacement original frame, power steering, newer rear axle with fast gears and a Cummins 4BT with your choice of transmission. If Allison then the 2000 may be easier to bolt on than the 1000 that is intended for the Duramax, otherwise the 2000 is essentially the same as the 1000.

Look over here:
http://www.4btswaps.com

Grigg

Given that you will be doing a lot of work to make any frame support what you have described I'd suggest you consider fixing your original frame rather than swapping.

Cleaning those holes up with a hole saw would not be hard, then filling the holes with plugs welded in place would solve the problem. Yeah this would not be a trivial task but then a frame swap even using a stock frame isn't trivial either.

Welding lots of slugs in the frame doesn't sound like fun when better frames are not that hard to find.

But if he's swapping engines for a newer diesel the front clip comes off. The bed is already off. He'll need a different rear axle. The steering box comes out to replace with a PS gear box.

At this point he's got a few wires, clutch and brake pedal and 4 bolts holding the cab on, it would be really easy to swap the frame for a better one.

Or he did say this is his only truck, in which case if it runs and drives as is use it for now while building the diesel one on another frame, then swap the sheet metal later on.

Grigg

I use the city bus for now, the truck does not run the radiator is blown, the engines has problems and the starter or alternator went out and since I work from home time is not the issue. The issue is I am new to restoring trucks. Mine is down to a bare cab sitting on the original frame, then the engine and tranny are still in.

You know what? A 3/4 ton is noticeably bigger than a 1/2 ton, at least to my eyes, and while a smallish S-10 frame might work underneath a half ton, I would think for a 3/4 ton you'd want a larger truck frame.

I agree, I would not want to repair that frame either if it were mine. Someone else could have at it if they wanted to. I would probably be looking for another frame too.

Having converted to a small block V8 on the original 3/4 frame myself, I can honestly say it wasn't a real fun conversion. Everything needs engineering from scratch to make work. It is possible, but you have to really have the abilities to jump in there and start modifying.
And the one thing that comes to mind is that while the engine bay is very tall, it is also very narrow. There isn't a lot of side room at all.

So the first thing I'd be looking for is maybe using a Dodge Cummins Turbo Diesel truck for the re-body. The reason is because that's a straight six engine too, and I think it might work in your available engine bay. Plus that's a buttload of power those motors have. I'd start out by taking measurements of the frame, width, length, and wheel base. Minor changes could be made as you go. If you get a Dodge Ram with a really beat up body, but mechanically sound, this could be an interesting swap. Just plan on doing a lot of sound insulation of your cab!

If not that, and you really have your heart set on a V8, then I would suggest a Chevy C-10 from the 1970's. And do the same thing. Find a good fabricator willing to do the heavy work for you and welding the custom body mounts, and then go shopping for a donor truck.

Keep in mind surface rust is no big deal if you can sand or sandblast it off and repaint it. That steel is so thick that surface rust would take a long time to grow enough to compromise the frame.

If you compare the specs of an S-10 frame to the 3/4-ton frame its only the wheelbase that is a real problem. The later C-10 will give problems with width. Perhaps not insurmountable, but will add to the complications.

And I say that with a C-20 IFS setting next to my 1-ton frame and every intention of mounting it knowing I'll have width problems.

Every change you make compounds the adaptations and fabrication required. If you are not prepared to do those things yourself, you need to be prepared to pay someone else to do them.

Clearly others disagree, but unless your intended usage is defined differently than I've heard, or your confidence at fabrication increases, you have limited choices and I like fixing the stock frame though I see three options that seem consistent with the parameters I've seen you state.

1) Replace with a good stock frame. Lots of work but really just work, nothing tricky and no real special tools required if you are prepared to replace a motor.

2) Fix your frame. Lots of work, but welding and grinding just take time...

3) Go the S-10 route with a kit, and shorten your bed by buying short bed sides, or adjust the length of one of the longer S-10 frames.

The other frame swap choices are all much more complicated mostly because far as I know there are no kits. I suppose another approach would be a stock 1/2-ton frame again shortening the bed, which would not require a kit, but would mean lots of changes from what you have.

You have a number of options presented by me and others. Make a list and review the tools/skills required and the other advantages/disadvantages of each option. It may become real clear that some of the options, even those I suggest, won't work for you, but others fit real well.

Thinking and planning are key to success on a project like this. I always want to encourage people to fully understand what a successful finished project would be before they decide how to proceed.

option 4) sell the non running 3/4 ton and buy a truck that is a runner. In this economy it is always cheaper to buy one that is already done. There are plenty of trucks available.

Great idea!
Or don't sell it but keep it for spares; and buy a good running one too.

Grigg

Buying another truck is always a good idea and typically the option I'll choose. Buying two is even better. I've quit telling my wife how many we have.

I'm not so sure about selling one. Is that allowed?

Thank you all for the advice but the wife has spoken and her words were free is better, One of my friends was over and told her he had a fully rebuilt I-6 250 and auto transmission and even offered to fix the chassis for free. Hes coming back in 3 - 4 weeks with the engine and to fix the chassis so 6 months or so on body work should be running great.

Take pictures. We'll all want to see his work!

FYI your 3/4 ton has very little difference to a 1/2 ton. The body(cab/bed) are the same except the bed is longer. The frame is 11" wider at the rear tires on a 1/2 ton and shorter by ____". The front suspension is heavier and a bit different.
I would vote to keep and repair the frame. By the time you finish filling the holes you will be on your way to welding perfection.

The shape of a 1/2 ton AD frame compared to a 3/4 is much different.

The 1/2 ton is narrow at the front and wider at the back, tapering the whole way. The 3/4 ton only tapers from front to about the middle of the cab, from there back the rails are parallel.

I'd say that a 3/4 ton is a lot different than a 1/2 ton when considering frame, axles, brakes, and suspension.

Yes the sheet metal is the same other than bed and running board lengths.

Grigg

["The 1/2 ton is narrow at the front and wider at the back, tapering the whole way. The 3/4 ton only tapers from front to about the middle of the cab, from there back the rails are parallel."]

I believe that is what I said...
Wider at the back, front suspension is heaver and a bit different. I have dealt with those issues on my 3/4 ton and admit it is harder to find correct parts as most are designed for the 1/2 ton; but it can be done.

The difference between 1/2-ton and 3/4-ton that neither of you has mentioned is the way the rear axle is mounted and the open versus closed driveline.

The 1/2-ton axle sets over the springs and the 3/4- and 1-ton rear axle sets under the springs. Springs on the 1/2-ton are under the frame while on the 3/4- and 1-ton they are outside the frame.

I would tend to say there are lots of differences, but that is a relative assesment, and they are sure similar from the front cab mount to the front spring hanger.

Well, I think we're all on the same page now...

You had said "FYI your 3/4 ton has very little difference to a 1/2 ton"
That's the only part I disagreed with, as I think there are many differences "when considering frame, axles, brakes, and suspension"

Steve has expanded on what I was hinting at.

Grigg

My reference referred to the original question of his frame not the suspension or driveline.

I think this confusion started when someone referred to the 3/4 Ton as being bigger than the 1/2 Ton, in the context of putting the sheet metal on a different frame. Of course, other then the bed length the sheet metal is the same. So now I will ask my question out of curiosity. What kind of motors fit in nicely with the S10 conversions.

What kind of motors fit nicely?

That's another question where the answer will be subjective and depend on what someone thinks nicely means.

I suppose any motor you could ask to hop into the engine compartment, and which responded by nicely fitting in.

I've seen GM V-6's, and Chevy small block and big block V-8's installed in S-10 framed trucks.

I know Joe has a 425 Cadillac in his. And I'd imagine most any sidemount type motor, including the later GM inline sixes could easily be adapted.

But what does fit nicely mean?

I vote for a Valiant slant six!

My definition of "what fits nicely"
Is what fits without having to cut anything out of the way and it bolts in, no fabrication necessary.

Grigg