The Stovebolt Site Forums The Shop Area General Truck Talk Task Force to Late Astro 4x4 swap?

For some time I've thinking about a Tahoe swap for my '59 swb fleet, but lately I've noticed late model Astro 4x4 vans w/six lug wheels. Would this address the track width issue with full size trucks/SUVs? Has the Astro track width changed with the demise of the S-10? Is it built on a 1/2 ton chassis now? I've heard the Astro was a good swap, but nothing on late models. :rolleyes:

An Astro with 6 lug wheels? I think you might be thinking of the Chevy Uplander, which replaced the Astro. It has 6 lug wheels, but is a front driver, not rear/all wheel drive like the Astro. I'd be somewhat leery of using an Astro for a swap like that, the Astro doesn't really have a chassis so to speak, it's built on a unit body typw platform, there's just a front sub frame as far as engine/trans/front axle goes. Also, the engine is offset to the right by about 4" to cleat the steering shaft, the center cection of the rear diff is offset the same amount. They also have issues with idler arm wear, which is double on them because they actually have 2 of them.
Inmy own opinion, if you want to go 4x4, find a mid '70s Chevy 4x4, get the axles and other 4x4 related stuff from them, and mount them to your stock chassis. You'll get a more original looking,and better performing for off road use, truck. Try to find either a '73-'76 or if a later 1/2 ton, one with a 4.10 axle ratio. The reason is that those trucks have the stronger Dana/Spicer 44 front axle, and up to '76 will have a 12 bolt out back. Aslo, look for manual hubs on the later truck. Most of the manual hub trucks have the NP205 cast iron T-case, very strong. Or alternatively, a '74 ('73 on Blazer) -'79 with the NP203 full time case would be exellent, too, but fuel mileage may suffer.

Thanks for the input Bill, I will look next time I see one to be certain of the nameplate. Looks like I may have to go with an S-10 4x4 4.3L. I will not take the truck off road, so it does not need to be bulletproof. Only reason for the 4x4 is that every pick-up I ever owned needed traction help in the rain. I really want a complete drivetrain/chassis swap for maintainability.

Regards, Dirk

I have been running the combination that Bill is talking about for almost 15 years, and think it is great. My 4x4 stuff under my 55 Cameo came from a 76 Blazer, and the only changes I made were to install a part time kit in the NP 203 transfer case and part time hubs. I adjusted the spring pads to the same dimensions as the 55 running gear in an effort to keep changes to the stock frame to a minimum. I am running the 8" 6 bolt Ralley wheels, and they do stick out a bit, but clearance is no problem because the rear end is raised 4" for clearance, and to match the amount the 4x4 front axle raised the front end. It is a good reliable combination and parts are not a problem. I am switching back to a stock 2WD setup because I no longer have a need for the 4WD. It worked well for me.
Bob

Thanks for all the good advice. I have considered the swap you mentioned, but the gas mileage and harsh ride are not what I am hoping for. I do not have an original chassis for my truck, so I will have to substitute something about the right size. Oh...and it must be a Chevy.

Bowtie on the outside, Bowtie on the inside.

Anyway, I saw a newer Astro van in my neighborhood and stopped to double check the nameplate and the number of lugs on the wheels. It belonged to the local cable company and was not 4x4. Yes Virginia, there really is a newer style Astro van with six lug wheels. Next chance I get, I will stop by the local dealer and check on the track width and wheelbase. Who knows? It might work!

Patchy, I love your sig!!

As for as swapping frame and such, a stock frame will fit and work better and look nicer than anything else.

If you can't find a stock '55-59 chassis for your truck locally, you're not looking hard enough. I know of at least two in local fields, I see rolling chassis on my local Craigslist for anywhere between $50 and $500 dollars. Sometimes I see complete 55-59 parts trucks on there for cheap, too!

Buy a running 70's Chevy 4x4 for $1000, part it out for some beer money, and use the drivetrain, axles, tires, etc, etc in the '59.

It's so easy they practically sell 'em in Betty Crocker boxes, just add water and bake!!

That being said, the flip side, metal is your *****, you can do anything with a welder and time, but how much time and effort to do you want to put into that?

Your new frame will need new cab, radiator, and possibly bed supports welded on to mate to the old truck, and it's quite likely the floorpan may need to be altered to fit your "new" frame.

Don't forget about all the details, stuff like bumper mounts, moving the master cylinder, hanging pedal assembly, possibly clearancing/recessing the firewall and making a transmission tunnel, along with lots of other stuff. Might not be a problem with a Task Force, but sometimes the frame hangs down lower under the truck, and it looks like total ***.

Your results may vary. It is your time and money, but I pose the arguement for stock frame, 70's running gear.

The Astro does have 4.3 V-6 power, 700R-4 or 4L60 OD AT, and either rear or AWD. True they are 5 lug wheels. The Uplander didn't replace the Astro, it replaced the Venture, which both are uni-body, front engine - front drive (and some Ventures were AWD).

The last of the Astro vans did 6 lug wheels, and they looked the same as the Silverado 4x4 trucks.

I thought the Astro had a full frame like the S-10, but I was wrong, sorry. But I'm sure the running gear, and even AWD assembly would bolt to an S-10 frame though.

Well, the Uplander didn't directly replace the Astro, but since the Astro was discontinued, along with the Venture, it has taken over the Chevrolet end of the mini-van market. Also, I've been under more Asto vans than I care to admit, I've never seen a full frame Astro/Safari, even the 4x4 models. The Astro, or M van to use GMs chassis designation, was not based on the S10 pickup, it has it's own unique chassis design. There's major differences in the steering linkeage, having 2 idler arms and a separate drag link, plus differences in the engine mounting, which is approximatly 4" to the right side of the chassis. There's also a corresponding offset to the rear axle center section. Now, I'll admit, I've never seen a 6 lug variant, must be a very late production ('05) and most likely, it shares the bolt pattern with the Trailblazer/Colorado, which is smaller than the std Chevy 6x5 1/2.
I tend to go along with the others. There's several '57s in my area running on mid-'70s 4x4 running gear, and if done correctly, they actually look stock. They don't really ride that bad if you leave the stock springs alone (no lifts) and will fit a 32x11.50x15 tire without any problems (floatation tires=better ride). You could find one pretty cheap, even up to the mid '80s would be ok, to. Find one with a rotten body.
No offence intended to anyone, but like I said, I've been under and have worked on alot of those vans.

I agree with LONGBOX55, I've owned several Astro's and they only have a front sub frame. There appears to be a full length channel frame but is part of the body and cannot be removed like truck frame. I'm in the process of putting an S-10 frame under a 50 chevy truck and it will need spacers on the front wheels to make it look right. My brother and his son are building a 57 GMC and are using a full size 70's chevy truck frame and it fits great. No spacers etc.

The easiest and most original way would be to buy used NAPCO running gear. That is what I am doing to my 55 2nd series. It is pretty much a bolt in job (emphasis on pretty much). But you will have to deal with drum brakes. I purchased cross drilled rotors and am installing power brakes to make it safer. Then you can claim you have a semi-original truck. And the axles are just awesome looking with their military design and the steering tie rod behind the front axle.