55.2-59 57 Chevy stepside 4x4 (NEED HELP)

[Bridgeman57]

Bought this beauty a few days ago and was told it’s on original chassis. Which I do bealive it’s the original frame but different front end. I need help figuring out what I’m dealing with. If it’s original 4x4 or not?

[MJN]

Not an original front axle, looks to be a GM Corporate 10 bolt from 78 and newer K10 pickup/Blazer/Suburban. Looks like someone swapped in a newer drivetrain; steering column, engine/trans/transfer case, front and rear axles. Just based on the hood emblem it was originally a 6-cylinder truck. From the looks of it the frame and body are the only original pieces left.

[Bridgeman57]

So In your opinion where should I start at? How do I figure out exactly what parts to buy? What parts to take off to make it an easier build? Keep it how it is and build from there?

[MJN]

Thats really up to you and what your end goal is and what kind of rig you're building. Do you want a 4x4 daily driver or just a show piece? Full on factory restoration or resto-mod? In order to find out what axles and drivetrain is in it better pictures would help. I'm only guessing based on the front axle picture that the drivetrain is from a '78 and newer pickup/blazer or suburban. Having pictures of the transmission/transfer case, rear axle, etc would help narrow it down.
If you're going for a total original restoration, find an original drivetrain from a '57. If you want original four-wheel drive, you'll pay for a NAPCO conversion if you can find one.

I'd start with getting yourself a factory service manual, owners manual and a few other reference books to help decode things along the way, reproductions are available from LMC truck or several other parts suppliers. A copy of Cars and Parts Catalog of Chevy Truck ID Numbers 1946-1972 is helpful https://www.barnesandnoble.com/w/cat...=9781880524022 . Download a copy of the GM Information packet too, https://www.gmheritagecenter.com/gm-...tion-kits.html

[Bridgeman57]

I am just looking to build a decent daily driver. I am only 25 years old so the money isn’t there for a restoration. I have the books already ordered and on there way. I will do some research and take more pics for you by the end of the week. I just want to have it on the road the most reasonable way possible right now. I have the rest of my life to restore it. Do not plan on getting rid of it. They are hard to find with a rust free cab. Thank you so much. Look forward to talking more

[mr48chev]

It looks like someone had the intent of building a pretty nice truck and started out doing it right for a change. It shouldn't be real hard or real expensive to finish to where it is a drive-able and usable truck.

That type of axle and trans and transfer swap was real common around here in the 70's and 80's before people got lazy and started sticking the older body on a later chassis.

Still what were your plans for it when you bought it? Finish the 4x4 build or ???
If Your plan is to finish it as a 4x4 I don't see any reason to make big changes unless things are badly cobbled together and that needs to be corrected.

You can reasonably assume that all the pieces came out of the same donor rig. Starting with the suffix code on the engine block you might come reasonably close to figuring out what the donor was. I think the guys are right on the money in that It has 78 or later pieces due to the steeing knuckle design. That isn't a bad thing if you plan for it to be a daily driver though.

[Bridgeman57]

Yes I am going to keep it a 4x4. I would assume it’s all from the donor but I will look further into it. I plan on putting a nice used LS3 in her for now and going from there. Throw some clear over the paint and calling it good. It hasn’t been registered since 84. Has been in a barn for over 20 years. Idk if it’s the original control arm or not but it has the big U shapes control arm or whatever it is with 2 shock mounts in the middle and 1 on the side near the front tire. Idk what they were doin with it. Would look nice with 3 shocks (6) for the front suspension but it may be to okie rigged haha.

[Russell Ashley]

I'd start by pressure washing as much of the frame and running gear as you can and then you might be able to find some numbers that would definitely ID the axles, transfer case and other parts. Would make it look better for sure. You will need to clean and lubricate the knuckles and change all of the fluids before driving it, as well as doing a brake job on it. With a little clean-up and fix-up it will be a cool driver.

[Bridgeman57]

Yes definitely my plan this weekend. Having a family friend that owns a bad ass shop come take a look at it and will go from there. Any advise on LS engine mounts. Including the harness. Is it a pain to deal with all the wiring and everything comes with it?

[Bridgeman57]

So got the axles power washed and here are the pictures. Hopefully y’all are better help then the internet.

Pictures of front and rear diff. Front diff has the bar across.
The small numbers are on the 4x4 transfer case
Not sure if the Red Cross member is homeade or not haha.
I found all the numbers I can.

620216- Front Passenger drum
346821- Transfer case
GM74- Rear Axle
I have more pictures and numbers so please if you need more info. Not a problem.

[1project2many]

Hopefully y’all are better help then the internet.

We are the internet.

That's a 12 bolt Chevy Truck rear axle. GM stopped using them around 85 or 86 IIRC?

The transfer case appears to be an NP203 chain drive case originally from a full time 4X4 truck.

NP205 has a distinct raised area on the back of the case:


I'm also thinking the running gear is late '70s.

[Bridgeman57]

Haha please ppl bare with me here. so I found an 81 blazer full chassis except t-case. (FOR FREE) it’s mine already, just have to pick it up. It original came with 3/4 ton axles but he swappped em out with 1 ton axles. Would the frame swap be worth it? Frame extension or shorten? If I have to. I have a long bed. Would the t-case I have now be able to work with the donor frame? If so what transmission will it work with? I plan on putting an LS with a 4L60 or 80.
Also my current frame has been modified a bit. Shock mounts and tranny mount cut off. Things here and there. I bealive it’s an aftermarket shock mount. A huge concern for me is the steering box. Outside of the frame or inside?

[mongocanfly]

you had me confused ..you've got 2 threads going at the same time on this...

(It original came with 3/4 ton axles but he swappped em out with 1 ton axles)
this is wrong....blazer never came with 3/4 ton axles

if your intent on doing a swap its much easier to shorten a longer frame than it is to stretch a short frame...
good score on the free blazer...and id like to see some pics of those 1ton axles under it..cause the pic from the front looks like a corp 10bolt front axle

[mongocanfly]

im thinkin a better description of what your wanting to accomplish would be helpful.. your asking questions on about 3-4 different trucks now it seems
just clarify your end goal

[1project2many]

Is there anything inherently wrong with the frame that's under the truck now? Why can't you clean up the current conversion and run with it?

I also think it's time to figure out what you want from the truck. Is it a once in a while wheeling rig with big tires? Is it a high hp, big dollar machine? If you just keep collecting parts because they're good deals you're likely to end up with a truck in pieces and no ide how to finish.

[mongocanfly]

"I plan on putting an LS with a 4L60 or 80."
if you can find a 91 burb it will be a 4l80/np241 pass side drop...

[57tailgater]

I am confused about the 2 threads also - you may want to consolidate. Note the Blazer chassis will have a shorter wheelbase than the '57 truck. Not sure of the exact amount but it is shorter. People have done it without adjusting and those with a keen eye can spot it. Note on the Blazer the steering box is on the outside of the frame. 3/4 or 1 ton axles seem overkill but if you're wanting that go for it.

[whateverpratt]

I vote to keep the stock frame and springs. You can swap any front axle from napco axles to the last of the front dana 60's that GM used. Just pick the motor-tranny-tcase combo that suits you and swap it in.