The Stovebolt Site Forums The Shop Area General Truck Talk GMC VS CHEVY

Taking a look at '50's trucks, other than engines what are the differences between GMC and Chevy trucks.

What is interchangeable such as body parts interior parts etc. ??

Need a history lesson.

Thanks

Grille, radiator, front cross member, tail gate, gauges, GMC positive ground and Chev neg. Everything else is pretty interchangeable.

Spoken like a lawyer Ken! a lot of the sheetmetal will interchange with some work. GMC hung the front sheetmetal differently than chevy... it had something to do with the radiator supports mounting to that different crossmember. It wasn't till 1958 that gmc and chevy front sheetmetal was hung the same. Although the radiators were a still a little different.

Can You be specific with a year or body style?

GMC offered an automatic in '53, Chevy did in '54. If you go year by year there are likely a number of things like that to consider.

GMC offered trucks larger than the 2-ton early in the 50's while Chevy did not until near the end of the decade. Those larger trucks will show a number of differences from the Chevrolet trucks including some huge six cylinder motors and similar looking but different body panels.

When you get to the Task Force/Blue Chip trucks the range of engine differences become more extreme. While the standard motors are the Chevy 235 and GMC 270 the V-8s are the Chevy 265/283 while the GMC trucks had the much larger Pontiac and Olds motors.

I've seen GMC trucks that appeared to have original Dana axles just as early as open drivelines appeared and those axles had some ratio options that Chevy did not offer.

As Ken said a lot things will interchange, but if you are trying to build an accurate restoration some things are very different.

Can You be specific with a year and body style (as requested by bigbadswingdaddy)?

There are different differences by year and by model (interior and exterior differences).

Well, lets start with a 1950 GMC 1 ton. I believe 1/2 ton GMC body panels will bolt up to a GMC 1 ton. How about Chevy body parts to a '50 GMC 1 ton?

Yes I do have reasons for these questions. If everything turns out I will let everybody know! May be some time though.

Thanks.

Take a complete 1950 Chevrolet/GMC 1/2 ton front sheet metal clip and attach it to a 1950 GMC 1 ton with no problems except you will have to exchange the GMC front cross member with a Chevrolet front cross member. You will have to use the Chevrolet radiator too.

Doors, cab, dash, seats, glass, floor pans, patch panels etc. are the same.

Thanks GMONIZ! That is great to know. So if I cannot find aftermarket GMC parts for a 1 ton I could use a lot of the parts from a Chevy parts truck then.

Actually it sounds like I can use aftermarket Chevy parts for a GMC, including the interior!

Thanks!

The GMC engine is longer. That is the reason for the different crossmember. The front mount of the engine bolts to the crossmember. The GMC radiator sits further forward and mounts to the crossmember. If you put in a Chevy crossmember you will need to use a Chevy engine too to make it work. The GMC engine will no longer fit.

Now this all makes sense. I wondered why the different cross member.

Minor difference: dash gauges' faces are different colors.

Horn buttons are different.

I'm constantly amazed how much info. you all know!

Who else would know the dash gage faces are different colors??

Oil pressure guage is different too! The gmc will show 80 lbs, while the chevy will only show 30 lbs. This is due to the full oil pressure motors that gmc was running compared to the splash oiled chevys.

Was it around '53 when Chevy went full pressure?

Chevrolet trucks had high-pressure engines in 1954.

Thanks Tim that's important info. that I need at this moment.

Also GMC amp gauges show numbers, Chevies show D and C. GMC fuel gauges are marked FUEL and Chevies are marked GASOLINE. Gmc brake and fuel lines are clamped on with screws and nuts, Chevies have clips.

I'm referring to AD/ND series trucks.

Iron Clad, I missed the engine part, I thought you were only going with sheet metal differences. It's a lot easier putting a 235 in a GMC then it is putting a 228 in a Chevrolet. I have seen quite a few Chevrolet front ends on an old GMC truck, but I don't know which engine they used. My guess would be either a 235 or a V-8 There are a few idiosyncrasies between the two trucks, most don't make a bit of difference, but the engines do.

That's why it's best to be up front with the question, otherwise I guess at what you want. So what's your plans?

The engine wasn't the concern. But knowing that the GMC engine is longer which puts the cross member farther out is good to know because it has a direct effect on the front sheet metal. Or it helps me understand why the front sheet metal isn't as easy to interchange.

The whole reason for these questions is because I'm looking at a '50 GMC 1 ton that needs body work. The engine runs fine so that's not a concern right now. I'm just researching as to the availabilty of body parts and whats interchangable.

Body parts: Except for the beds, the 1/2 through 1 ton body parts are the same within GMC (or within Chevrolet). The hoods/grills/emblems/tailgates differ between GMC/Chevy (fenders are slightly different). Cabs/doors/glass/seats are the same.

What body work needs to be done?

Front fenders. One needs replaced the other I believe can be fixed. The usual cab corners, well one corner anyway. The interior needs redone. I'm not sure of the rest yet since I haven't actually seen the truck yet but I have some pictures. The truck is about 5 to 6 hour drive from my home.

5 or 6 hours which direction? I only ask because from where you are that could be very dry county or very wet country, and rashly assuming the truck has lived near where it is today that might greatly impact the condition of the body.

East! So in dry country..

I've been all over that country. I grew up just over the border a little way in Idaho. Malheur Country used to have an emergency call box system that I helped install back in the 70's. Back then I must have been on every road east of 97 that shows on a map and a lot of roads that don't.

Unless its been buried in a river bed I'd expect it to have been pretty dry, even when covered by snow.

It doesn't sound like you're making lots of changes, like hot rodding, and it doesn't sound like you're trying to restore this truck to original condition. It sounds to me like you want to make it complete and looking generally like a truck of its time.

If I've got that right I'd say you have a lot of interchangeability available. Many of the things that are different really don't matter except to an expert and they will not affect function of the truck.

I say grab that truck! Of course I already own two 1-ton GMC trucks and might be a little biased...

Front fenders are the same between the GMC and Chevrolet. Some say there may be some bolt hole differences, I did not have that problem when I did mine. The GMC will have parking lights in the fenders and the Chevrolet has them in the Grille.

If you are looking at a one ton GMC that needs some body work and you don't need to change out the hood, radiator and grille. Most of the Chevrolet parts will work. Cab corners are the same. Gravel shield/valence is not the same between the two trucks. You can weld on an engine mount to the front GMC cross member to adapt a Chevrolet 235 but not visa versa.

how about 1/2ton frames? chevy same as gmc, minus said cross member?

I've heard said that the GMC frames are thicker and longer. I've never measured a pair to confirm or deny that claim. I'm not inclined to believe it mostly because I know the 1-ton frames are made of the same thickness material based on measuring both myself.

However, I'm making an assumption and that can always be dangerous.

The front cross member is different UNLESS you are looking at one of the Canadian GMC trucks that came with a Chevy motor in it. That fits into the topic what is different between US made and Canadian made GMC trucks and I prefer to defer to some of the Canadian members for those specifics.

I recently bought a 56 Ford on eBay that spent all of its life in Bend, OR. It is the most rust free anything I have ever bought. I am assuming that is the general area you are describing.

I have heard the frames are thicker on the GMC vs the Chevrolet too! I am working on a Chevrolet frame that is going under my GMC and so far they look the same. I will have to check the thickness one day.

Crenwelge, your getting warm to the location but still about 3 hours drive away! Same climate though.

GMC and Chevy gauges are different on all but the speedo. Here's an article I wrote for Jim Carter's site on that topic:
http://www.oldchevytrucks.com/cgi/htmlos.exe/0015566.4.2211832026100014059