Quick Cab and Chassis question

[1966Stepside]

I've been looking for a tow/haul rig for a while now and I've seen a few square body cab and chassis trucks for sale locally. I haven't been able to find much info on the cab and chassis, so I'm hoping someone here can shed some light.

Are all cab and chassis duallys a 30 series or could you get a 20 series? I'm seeing a lot of 350/TH400 combos for sale, but I've also seen some c20 cab and chassis that they say have been converted to dually. Since some of these trucks are almost 40 years old a lot of work could have been done to them in the years. What I really want is a true c30 dually. How do I tell that's what I'm getting? 14 bolt full float the key to telling?

I appreciate any advice. I've got a 66 project I'm restoring, but I'm not real familiar with the square bodies, especially the HD ones.

[Keith Seymore]

Originally Posted by 1966Stepside

I've been looking for a tow/haul rig for a while now and I've seen a few square body cab and chassis trucks for sale locally. I haven't been able to find much info on the cab and chassis, so I'm hoping someone here can shed some light.

Are all cab and chassis duallys a 30 series or could you get a 20 series? I'm seeing a lot of 350/TH400 combos for sale, but I've also seen some c20 cab and chassis that they say have been converted to dually. Since some of these trucks are almost 40 years old a lot of work could have been done to them in the years. What I really want is a true c30 dually. How do I tell that's what I'm getting? 14 bolt full float the key to telling?

I appreciate any advice. I've got a 66 project I'm restoring, but I'm not real familiar with the square bodies, especially the HD ones.

Going from memory here:

All Cab/Chassis were 30 series. You could get a single or dual rear wheel cab/chassis.

There were no 20 series cab/chassis (any 20 series would have come with a pickup box).

Here's a link to the generic info packets from the GM Heritage Center archives. Scroll through some of the truck model years of interest; it should show you what was available.

http://www.gmheritagecenter.com/gm-h...tion-kits.html

K

[1966Stepside]

Thanks, that's what I needed to know. That link you provided has great detail in it. Going to look at a 78 cab chassis in the next day or two, might bring home a new toy.

[GM72K10]

Originally Posted by Keith Seymore

Going from memory here:

All Cab/Chassis were 30 series. You could get a single or dual rear wheel cab/chassis.

There were no 20 series cab/chassis (any 20 series would have come with a pickup box).

Here's a link to the generic info packets from the GM Heritage Center archives. Scroll through some of the truck model years of interest; it should show you what was available.

http://www.gmheritagecenter.com/gm-h...tion-kits.html

K

Sorry but you could get a cab/chassis 20 series, 10 series also. All single rear wheel of course. Code is ZW9, so if that code is on the glove box or wheel well sheet it did NOT come with a pickup box.
We had a few c20 cab/chassis in the 70s and put service bodies on them.

[OldCreek]

Checking the frame modulus / thickness and height should tell u if it is a 1ton....

[1966Stepside]

Originally Posted by OldCreek

Checking the frame modulus / thickness and height should tell u if it is a 1ton....

What would I be looking for? I can take a pair of calipers and check the steel of the frame, but that's a bit extreme to most sellers, I would think.

I guess the real only way is to be with the truck and decode the VIN.

[OldCreek]

Typically, the frames are thicker and taller. I don't have that info available but I've seen it posted on this site over and again.

[GM72K10]

frame specs

[Keith Seymore]

Originally Posted by GM72K10

Sorry but you could get a cab/chassis 20 series, 10 series also. All single rear wheel of course. Code is ZW9, so if that code is on the glove box or wheel well sheet it did NOT come with a pickup box.
We had a few c20 cab/chassis in the 70s and put service bodies on them.

Dangit! You are right; ZW9 is "base body" (= no pickup box).

We used to see those single rear versions around here as catering trucks (we called them "Roach Coaches").

K

[Wrecked1982]

im not sure about older ones, but 81 ad up cab and chassis had a 4 inches longer Wheel base, to see if its a true 1 ton check if the rear shocks are Inside the frames rails

[Wrecked1982]

theres is also a digit in the vin that tells if its a normal pick up or a cab and chassis but i dont remember enough

[Cabnchassis]

Easiest way to be sure is to measure the frame height under the cab or around the fuel tanks. The frame on my 91 is 8" tall at the saddle tanks if you can see it you can easily tell without measuring that its taller by several inches. If it is a dually with the original 14ff then it will be 44" or real close to it wms to wms. If you stand behind the truck the outside rear wheels on either side should line up so you could throw a fleetside over it and it'd cover the wheels. There is only about a half inch of space between the back of the brake drum to the spring perches/bolts. What I'm getting at is it will look like some shoehorned an axle that was entirely too narrow for the truck because every thing just barely clears.

Should also have an R or V early on in the vin somewhere too.

If it is a dually like mine it'll have at least 9 leafs in the leaf springs plus an overload spring and the overload perches bolt/rivet to the frame so you shouldn't see any welds there.

I have the bed off mine right now waiting to put a fleetside on it, so let me know if you want a pic of anything specific.

Edit to add: Be sure to check the rear diff ratio if you can see the RPO code (probably can't pop the pumpkin on a truck you're trying to buy) Mine runs down the road nice with the 4.11s but they came with either 4.11 4.56, 4.88, and 5.13. Even the 4.88 is probably pretty easy to get around with, but the 5.13s will probably be too much unless you're hooked up to something serious or don't mind re-gearing