The Stovebolt Site Forums The Shop Area General Truck Talk 51GMC frame

I have a 51 GMC and am looking for a replacement frame. What years will work and is the Chev frame the same??

Thanks

Jeff

We need a little more info from you. Are you in Victoria, BC? In US trucks the frames are different because the GMC engine is longer. Canadian GMCs used Chevy engines so the frames might be the same.

I don't know all the details, but can give you some of the differences you need to be aware of. For instance Chevrolet never made a long wheelbase 1/2-ton while GMC did.

This is all assuming you have a 1/2-ton short wheelbase truck. If its anything else the details might be a little different.

The front crossmember is different between Chevrolet and GMC. If you use a Chevy frame you'll need to deal with that, probably by swapping the crossmember.

There are two differences between the '47 - '53 frames and the '54-'55 1st frames. The bellhousing crossmember is different, the later frame has an angled pad for the bellhousing mount where the early frame has a flat mount. If you want to use the '51 bellhousing this could be an issue.

The second difference is that the kickup over the rear axle is lower on the later frames. Probably not a problem using a later frame under an earlier bed, but would be a problem the other way around.

Also some trucks have a crossmember under the rear of the transmission. I've never seen it personally, but I believe it only occurs on the pre-'54 frames. I know its not on any of the '54-'55 1st frames I have and the '53 GMC currently in my shop doesn't have it either, though its not original in other aspects.

Two other frame related differences I know of are the two different types of shock mounts and the two different rear cab mounts. I can't tell you the years affected from memory.

And one more thing to think about. The frame is the same under a panel/Suburban as under a pickup. But the panel/Suburban will have some mounts you aren't going to find on the pickup. Both frame types will have all the holes for either application.

So that is a quick rundown on the differences as I remember them. I hope this helps.

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I completely missed that you are in Victoria. Cletis is right that Canadian GMC trucks had Chevy motors and I would presume that front crossmember would be the Chevy type. Is your truck US made or Canadian made? Or are you in some other Victoria?

Steve & Cletis,

Thanks so much for the most informative and valued replies to my frame question. Yes, I am in Victoria, BC Canada and my frame is most likely Canadian. The truck is a 1/2 T and currently has a 235 Chev motor in it which seems to fit like a glove. The rest (body etc) is all stock. The GM side emblems show "9300" which is a Canadian model.

Would the wheelbase between the Chev and GM (US model) be different???

Thanks

Jeff

Far as I know the wheelbase options are the same across all countries. But really that only means I don't know of any differences.

That model number must be Canadian but I don't know what it means. Canadian Chevrolet numbers I've been able to figure out, but the GMC numbers I've not seen enough of to understand.

What is the wheelbase? 116 would only be a 1/2-ton and 137 would only be a 1-ton. 125 could be either 1/2- or 3/4-ton on a GMC.

How many lugs on the hubs? Six lugs is going to be a 1/2-ton unless its a real big truck. Eight lugs is going to be a 3/4- or 1-ton. Ten lugs is definitely a big truck.

In a US made '51 Chevrolet 1/2- or 3/4-ton the standard motor was the 216. I don't know what they did in Canada but I have to wonder if the 235 is original.

Why do you need a replacement frame?

I recently took apart a 1955 GMC Suburban, and found short extensions at the rear of the frame, to support the back of the body. Other than that the frame is exactly the same as my '54 GMC 100 (short half ton).

wow, I didnt realize all the differences between US and Canadian made AD trucks. This is some neat information.

Chevman I own a '55 1st GMC Suburban and it does not have any short extentions at the rear of the frame. I'm curious what these you found look like.

Another frame variation is the Hydromatic trucks. They have removable bellhousing crossmember and a crossmember at the rear of the transmission. And of course, no clutch pedel mount.

This would be applicable to 53-55.1 GMC and 54 and 55.1 Chevy.

I will have a '51 GMC rolling frame this summer that I will part with real cheap. It appears to be in good condition. I bought the whole truck last summer near Tulsa Ok and am going to use the body to build a 4x4. I already have a '53 half ton for my daily driver and wanted to build something a little different. The only problem is that I am located in the Upper Penninsula of Michigan. The distance factor might be a problem.