Chevy vs GMC frame?

[blazer-k5]

Any way to tell them apart? Little bird told me that mine because it has leaf springs might be a GMC chassis? Any truth to this?

[ky-donzi]

To my knowledge 60-62 chevy gmc have torsion bar front, 63-66 coil spring front. Chevy 1/2 -3/4 ton rear coil, 1-ton leaf. Gmc were all leaf rear.

[tincan1966]

There is no definite "all chevys were coil, all GMC were leaf" either could be ordered either way.

MOST Chevys were standard equipped with coils and MOST GMC were standard equipped with leaf springs.

[blazer-k5]

Ah got it, it was option. There is not enough of these near me to compare. lol

[Old Truck Man]

I own a 62 GMC that has a factory coil spring rear torsion bar front. Its a GMC frame that doesn't have a vin number. I also have two Chevrolets a 70 and 72 with factory rear leaf springs. Most GMC,s do have the rear leaf springs. Most Chevrolets have rear coil springs. Chevrolet frames have the vin stamped on the frame in two places. drivers side near the front engine mount and under the cab. Ive never seen a GMC with the vin stamped on the frame.

[Old Truck Man]

Originally Posted by Old Truck Man

I own a 62 GMC that has a factory coil spring rear torsion bar front. Its a GMC frame that doesn't have a vin number. I also have two Chevrolets a 70 and 72 with factory rear leaf springs. Most GMC,s do have the rear leaf springs. Most Chevrolets have rear coil springs. Chevrolet frames have the vin stamped on the frame in two places. drivers side near the front engine mount and under the cab. Ive never seen a GMC with the vin stamped on the frame.

Ok here are pictures of the fabled GMC with factory rear coil springs. Not much left of the old girl. However if you look closely you can see the original V6 engine mount still welded to the frame. also the remmants of the trailing arms at the back of the cab. I installed the 63 frame engine mounts when converting to a V8

[blazer-k5]

Good to know I will lay underneath her tomorrow.

[Captainfab]

I agree with no VIN on the GMC frame. I've had 3 '60-'66 GMC's and there was no VIN that I could find.

[kieth]

1. GMC FRAMES DO NOT HAVE A VIN NUMBER STAMPED ON THEM, I HAVE 2 A 65 AND A 66 AND NEITHER HAS A VIN ON THE FRAME.

2. MY 66 GMC HAS TRAILING ARMS AND COIL REAR SPRINGS, MY 65 GMC CAME ON LEAF SPRINGS


SO MUCH FOR GMC'S ONLY CAME ONE WAY !!!!!! HA HA KIETH

[Old Truck Man]

I once owned a 62 3/4 ton GMC that also had trailing arms and coil spring rear. It was a 305 V6 three speed on the collum too. It was a St Louis truck rusted completely away. I put rings & bearings in the engine & installed it in a 68 GMC two ton. Replaced the 351. It pulled great got 4 miles per gallon or less.

[kieth]

Originally Posted by Captainfab

I agree with no VIN on the GMC frame. I've had 3 '60-'66 GMC's and there was no VIN that I could find.

I was scrolling thru my build looking for pictures of the fuel tank install, ran into this sequence of 3 pictures of where gmc frames are marked, none are the serial number and since these shots were made while the body was off it makes it a lot easier to see where all the numbers are located:

1. top of frame by motor mount flange:
http://kieth.smugmug.com/Trucks/66-GMC/i-GZXQvKD/A



2. side of frame under cab:
http://kieth.smugmug.com/Trucks/66-GMC/i-DC3CjTx/A


3. Top of frame under cab:
http://kieth.smugmug.com/Trucks/66-G...location-L.jpg

[richards72chevy]

Didn't they come with different axles too?

[Old Truck Man]

Originally Posted by richards72chevy

Didn't they come with different axles too?

Most leaf spring GMC,s the rear axle has a pressed on outer bearing to retain the axles.

[Captainfab]

Most of the '63-'66 GMC 1/2 tons I have seen had the Dana 44 rear differential.

Originally Posted by richards72chevy

Didn't they come with different axles too?

[kieth]

Here is a new wrinkle I have a picture of a 66 GMC on Air bags======ha ha

here it is on coils with trailing arms before frame off restoration.

http://kieth.smugmug.com/Trucks/66-GMC/i-mFPsKZz/A


also has a 12 bolt rear end and a 250 6 cylinder 66 was (first year for inline 6 I believe)
http://kieth.smugmug.com/Trucks/66-GMC/i-4SdTh2t/A

I still have the engine and transmission:
http://kieth.smugmug.com/Trucks/66-GMC/i-T3x6Tkd/A

[66Submarine]

Just found this thread while searching and thought I'd point something out.

Keith, that is actually a Chevrolet frame; the first picture is the actual VIN number of the frame, just like all my Chevrolet frames have. It appears to be 6Z153636, which makes it a '66 Fremont truck AFAIK.

The trucks Old Truck Man posted are both x-frame '62's, which are supposed to have coil springs; GMC went to leaf springs in '63.

[short&wide65]

My GMC's frame has a number stamped on it as well. My frame is currently on its side so I can only see the one number on the side at the moment.

3829589 4 12 26 110

I know 110 is the wheelbase but not sure about anything else.

In regards to factory documentation I have an original Canadian 1965 GMC brochure coming and there is information on the truck having the trailing arm suspension. I can post scans when I get it.

What's also interesting is that my 250 engine block has a large CANADA cast right into it above the casting #.

[66Submarine]

Originally Posted by short&wide65

My GMC's frame has a number stamped on it as well. My frame is currently on its side so I can only see the one number on the side at the moment.

3829589 4 12 26 110

I know 110 is the wheelbase but not sure about anything else.

In regards to factory documentation I have an original Canadian 1965 GMC brochure coming and there is information on the truck having the trailing arm suspension. I can post scans when I get it.

What's also interesting is that my 250 engine block has a large CANADA cast right into it above the casting #.

The 110 is not actually the wheelbase; SWB was 115". Check the frame where the VIN in Keith's picture is when you can and report back to see if it's bare or has the correct VIN stamped into it (or if it has another Chevrolet number, obviously).

Please post the scans when you get the brochure in; that sounds very interesting.

My '68 Impala that was made in Delaware with a Canadian-made 307 also has "CANADA" cast into the heads (haven't checked the block).

[LostMy65]

My 62 GMC frame has Torsion bars and rear trailing arms with coils.
No vin on the frame.

[66Submarine]

'62 was supposed to have coils and torsion bars like that; thanks for the extra confirmation of the lack of a VIN on the GMC stuff.

AFAIK '60-'62 all had rear coil springs with the torsion bars and x-frame, then when they made the changeover in '63 to the '63-'66 ladder frame and front coils they went to leaf springs on the rear (this is only for the 1/2 and 3/4 ton 2wd trucks, of course).

[markeb01]

For what it's worth, my 1960 GMC 1/2 ton short bed also has no VIN on the frame, coil rear, and came with a Dana 44.

[66Submarine]

Originally Posted by markeb01

For what it's worth, my 1960 GMC 1/2 ton short bed also has no VIN on the frame, coil rear, and came with a Dana 44.

Thanks for the extra info.

[factorystock]

Interesting topic, when you talk leaf springs vs. coil, one must be very specific on years and models. There are the 4x4 models that always used leaf springs, as well as C 30s all years. Then there is the spesky Canadian built GMC's which used the Chevy chassis. Here is one thing to keep in mind. A leaf spring rear end as well as the Dana axle (GMC set up )could have been "special ordered" not a "regular available option" on Chevy's if the customer really wanted it, and a few did, especially on 3/4 tons when hauling a camper. Here is one.http://www.ebay.com/itm/1966-C20-V8-...p2047675.l2557

[66Submarine]

Originally Posted by factorystock

Interesting topic, when you talk leaf springs vs. coil, one must be very specific on years and models. There are the 4x4 models that always used leaf springs, as well as C 30s all years. Then there is the spesky Canadian built GMC's which used the Chevy chassis. Here is one thing to keep in mind. A leaf spring rear end as well as the Dana axle (GMC set up )could have been "special ordered" not a "regular available option" on Chevy's if the customer really wanted it, and a few did, especially on 3/4 tons when hauling a camper. Here is one.http://www.ebay.com/itm/1966-C20-V8-...p2047675.l2557

Thanks factorystock, that's by far the best supporting evidence I've found to date. Do you have any other examples you've seen saved, or any other information? Very interesting.

Like you said, it's probably a good idea to run through and list the types of suspension vs. model again.

AFAIK:

1960-1962 GMC = x-frame with torsion bars and rear coil springs
1960-1962 Chevrolet = same as GMC
1963-1966 Chevrolet = ladder frame and coil front and rear springs
1963-1966 GMC = ladder frame and front coils with rear leaf springs
(only applies to 2wd 1/2-3/4 ton trucks made in the US)

1 ton/C30/2500 (and up) trucks all had leaf springs on the back and 4x4's all had leaf springs all the way around.

Starting in 1968(?) you could order leaf springs as a standard RPO option on 1/2-3/4 ton 2wd Chevrolet trucks.

Apparently, you could also special order a Dana 60 GMC rear that came with leaf springs under a Chevrolet C20, at least in '66?

At least some plants in Canada seem to have built GMC's on Chevrolet frames?

[blazer-k5]

I'm bringing up the dead. I can't believe I missed the last half of the post. Still good info.