The Stovebolt Site Forums The Shop Area General Truck Talk Front Straight Axle Question

In the constant battle to make my 3800 a 3100, I was going to use a straight axle from another 3100 that I had taken off the rusted frame. I brought up the idea a while ago and was told it could be done, then I had a group of people say that it could not be done. I guess I am trying to open that conversation up again before I start ripping it off the truck to make the swap. BTW it is actually off a GMC not that I believe that would make a difference. Thanks

While it may be possible to install the 3100 axle in a 3800 frame, there are many things working against you in making a 3800 look like a 3100. Take a look at an assembly manual and you will see the problems.

Jackyl there are a fair number of people who say they have swapped the 1/2-ton front axle onto 3/4-ton trucks. The 1-ton is very similar and I'm imagining it would not be hard to swap the axles but you need to be prepared for some adapting as you proceed.

The bigger the truck the more likely Chevy vs. GMC will make a difference, but in a case like this it should not matter. Be aware that one popular upgrade is to use the 1-ton tie rod because its easier to use later tie-rod ends.

The frame on a 3800 is made of heavier material than the 3100 and the frame rails are both taller and wider. Also somewhere under the cab the width of the frame begins to differ and is narrower all the way back from that point. And of course I'm completely ignoring the 21 inch difference in wheelbase.

I'm sure I am one of those who has said the axle swap is possible. But before you begin you might want to spell out your entire plan to be sure I and others are not answering questions making assumptions about what you are doing that don't fit your objective. While I recognize your name and know I've been part of previous threads about your truck, you'll want to refresh my memory about what you are doing. I can hardly remember the details of my own projects, let alone those I comment on...

You might also want to indicate your own skill set and access to tools or perhaps those of the friends or shop you plan to use. Some things are easy if you have a full shop and good fabrication skills, but may become very difficult working in a driveway with a Walmart 62 piece tool kit.

You say your location is New York. Working in a parking garage stall in the city would be a different ball game than a car port under eight feet of snow in Buffalo. And either is a lot different than using your brother's three-bay shop with a lift, three welders and a machine shop in the basement. If that does describe your brother can I borrow him?

Upstate New York, I have a 3 bay garage with more tools than I know what do with. Not to get off track, but I ended up buying out a retiring mechanics garage. I have things I don't even know what they are used for. Plus 3 welders and access to a large amount of fabrication tools.
I have not been able to find a 1/2 ton frame for any reasonable amount of money otherwise I would just build that. The sheetmetal on the truck is extremely solid and would make a good base. Another option I am looking at right now is grabbing a el camino frame and using that.
Originally I was targeting using a camaro sub frame and putting in there, but it seemed as though the weigh was going to be an issue because of the larger frame rails.
I am open to thoughts.

Sounds like you're set then.

I'm surprised you can't find a 1/2-ton frame reasonably, since I have cut up two of them in the past year because no one wanted them, and I know where two more are that could be had cheap. Of course they would not be cheap to you being so far from here.

Do you have a 9-foot 1-ton type box? Be a shame to cut those sides, because there are people, including me, who would love to have them and they aren't reproduced anywhere.

Here is an outrageous thought. The Camaro subframe is really just a touch wide under one of these trucks, but a g-body ('78 to '88 Monte Carlo and similar) is the right width in the front. It's a perimeter type frame, but if you used just the front suspension and fabricated the rest of the frame, you could design for a 1/2-ton wheelbase and not deal with the issues of the 1-ton frame. You would be doing some fabricating...

Most El Camino frames are perimeter type and that does create problems since that type of frame is almost always too wide under the cab, often putting the side rails under the running boards.

Have you considered an S-10 frame? A standard cab long box is just the right length. They are a little narrow front and rear, which is nice if you are lowering the truck. In the rear a Camaro or S-10 4x4 axle are about right width.

But then if you are not afraid of using those tools, I see no reason not to swap the 1/2-ton front axle under your 1-ton truck. You just won't have the 1-ton capacity any more.

I also have a 3 bay shop too, but only two welders. Mine is crowded by projects and becoming way too small. My brother has a machine shop in his basement, but so far that hasn't helped me much.

Come to Nashville, or more accurately, about 65 miles south on I-65, and I'll let you take your pick of 1/2 ton frames, one 51 GMC, and one 54 Chevrolet, free! Just haul them away! The 51 has a complete straight axle, with hubs, brakes and wheels. I'm fabricating a frame from a Nova front clip and the back end of an S-10.

Your 3800 conversion is going to be a massive pain in the butt, with little chance of success.
Jerry

Jackyl, What about selling your 1 ton and finding a 1/2 ton to restore/rod? You would save yourself a TON of work & frustration.IIRC, tou have a nice flatbed truck that should sell rather quickly-- it was in good shape and, if left a 1 ton , would be a relatively easy restoration.
You can find a 1/2 ton in any condition desired on the various sites-- work it over as you want and save time, money and effort.

Today I ended up getting the El Camino frame. Yes the frame is wider than I need it to be, but what I figure is to use the frame rails and mounts that I have now and graft them into the frame, box it in and cut the wings free. The rear of this has already been narrowed to 48in which I think is standard for a 1/2 frame, if not I can make it smaller. The person I got the frame from told me that he saw a 50 Chevy truck on the same frame a week ago without any mod to the frame, but that means it will hang over the sides. The wheelbase is 117 has relatively new disc brakes up front just need to figure out the ride height of the 1/2 ton and where I want mine to be.

Ride height will be pretty high to keep from having to modify the frame. You didn't say what year this El Camino is, but I'm pretty sure they are all perimeter type frames, unless this is one of the very early x-frame versions.

Sorry it is a 1980 frame. The down side of the frame to me is that the main rails are a bit flimsy if you ask me. I will probably end up replacing what is there with 2x3 to strengthen it. At that point I will narrow the main rails to match the 1/2 ton

Going from memory, I think the front suspension on that frame is about right to fit under a lowered truck, meaning its a touch narrow at stock ride height.

Check the width of the rear axle. If its the same as a Monte Carlo of the same year, and it may be, its really too narrow unless you tub the bed.

There is a section in one of Tex Smith's books about narrowing a frame similiar to what you are probably thinking. If you haven't seen it you might want to look for a copy of How to Build Custom Cars. That link is to Amazon but you can probably find one on eBay cheap.

The interesting part is that the rear is already narrowed. I noticed last night that the frame rails on the 1 ton needs to be 36 in so I will need to move over the rails and incorporate them into the frame, then remove the perimeter rails that were there. I am hoping that I will lower the entire truck quite a bit, I want it riding on the ground.

One advantage to starting with a 3/4- or 1-ton frame is that the frame is narrower under the bed than on a 1/2-ton, making room for much wider tires.

However, what I was referring to was fit of the tires outside the bed sides. With the stock wheels and tires on your El Camino frame the distance between the inside surfaces of the tires may be too narrow to allow the bed to drop between them.

Not a problem if you plan to raise the bed floor and tub the bed.

Ok spent some time with the frame today, confused more than anything. This may be a dumb question, but are the engines and axles offset on Chevys? It appears that the engine mounts are ~1in to the passenger side, is that to clear the steering column? I know that my Buick is dead on because I built that frame with a company out west.

I assume you mean on the El Camino frame. It may be offset, but I don't know. It may also depend on which motor was originally in that car.