Core Support Differences, GMC & Chevy

[Fat Mike]

What is the difference between the GMC and chevy radiator core support? I have done the gmc to chevy conversion and need to know if I need to get a core support from a chevy. The year is a 50 and it is the 1/2 ton on s-10 conversion.

[MrTucker]

They are different, not sure exactly where though. I think it has to do with the different front crossmember. The gmc radiator is different as well has how the grill/fenders all tie together. here is the best pic of my gmc core support. Let me know and I can take some better pics

[fredscarryall]

i did the gmc to chevy conversion all ready so you will need a chevy core support ,chevy inner and outer fender,hood,hood latching plate and a lower splash shield. the factory riveted in bracket at the bottom of the core support has different mounting point. so you will have to drill two new holes in you crossmember. you may also need longer bolt and couple shims to raise it up a bit.to level out the frontend

[panelrodder81]

Originally Posted by fredscarryall

i did the gmc to chevy conversion all ready so you will need a chevy core support ,chevy inner and outer fender,hood,hood latching plate and a lower splash shield. the factory riveted in bracket at the bottom of the core support has different mounting point. so you will have to drill two new holes in you crossmember. you may also need longer bolt and couple shims to raise it up a bit.to level out the frontend

What about the radiators? Are they different?

-Panelrodder

[fredscarryall]

my gmc radiator worked with my chevy core support without any mods. some radiator shops say gmc truck has one size radiator 18 wide x 27 high.chevy truck has two sizes of radiators 18 x 27 and 20 1/4 wide x 24 1/2 high.you would just have to measure. i think the biggiest problem you may run into is hood clearance.

[panelrodder81]

Originally Posted by fredscarryall

my gmc radiator worked with my chevy core support without any mods. some radiator shops say gmc truck has one size radiator 18 wide x 27 high.chevy truck has two sizes of radiators 18 x 27 and 20 1/4 wide x 24 1/2 high.you would just have to measure. i think the biggiest problem you may run into is hood clearance.

Hmmm... I was out looking at the rad I have which is for Chevy and is going in a GMC and I noticed that the only thing I can see that is in direct conflict is the cap which sits on top on the Chevy and is out the back on the GMC. I figure I can just cut a notch in the piece that goes over the top of the GMC rad to make room for the cap. No biggie.

I also noticed that they sent me a rad with a built in trans cooler when I only ordered one that didn't have one. So I got a free trans cooler!

The install will have to wait though because I won't be able to go up and get the truck this weekend from storage. So I won't have a final answer as to whether it will work or not for another week or so.

-Panelrodder

[slimneverdies]

Ok, maybe this is one of the problems Im having trying to get my front sheetmetal aligned. The arms that connect from fender to radiator support are different. Ones from a Chevy and the other is GMC. Do you guys know if they are different? Unless one of mine somehow got bent cause one is 1 and three quarters inches longer.

[panelrodder81]

Originally Posted by slimneverdies

Ok, maybe this is one of the problems Im having trying to get my front sheetmetal aligned. The arms that connect from fender to radiator support are different. Ones from a Chevy and the other is GMC. Do you guys know if they are different? Unless one of mine somehow got bent cause one is 1 and three quarters inches longer.

Sorry but I'm not sure I even understand exactly what piece you are talking about. Can you add a pic?

Also, I'm going up to get the truck on friday, so I might be able to get some info the GMC piece you are talking about once I know exactly which one it is! I'm hoping to get some good pics too of the install of a Chevy rad into a GMC... here's to hoping it works!

-Panelrodder

[slimneverdies]

Here is what im talking about

[skip99]

one looks bent..

[slimneverdies]

Originally Posted by skip99

one looks bent..

I guess I can try to put some heat to it but it's gonna be a hit or miss getting really close to specs
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[panelrodder81]

Originally Posted by slimneverdies

Here is what im talking about

I have nothing to back this up with but my guess is they will be different from GMC to Chevy. So many things are different up front that there is a good chance these are too. I can take a look at my supports when I get the truck out tomorrow and see what I can determine.

-Panelrodder

[skip99]

I dont think they are different, I swapped out my chevy fenders for gmc fenders, just because they were in better shape, and I just had the front together yesterday, everything matched up..as far as fenders , hood, and grille. I didnt mount the inners or latch plates, but I had all the pieces side by side when I swapped them to make sure... I think one is just bent..a little too much curve?

I just measured mine which fit ok..24 1/2 " edge to edge across the u

[slimneverdies]

Is it possible that the supports are different and the mounting points are the same? My fenders are mix match also. I would think it would have a dent of some sort if it was bent especially considering it's a stamp piece.
Posted via Mobile Device

[skip99]

what measurement do you get?

[slimneverdies]

Thanks for taking your time out to help. I don't know exactly what you mean how you got your measurements but I got 24 1/2" in one and 23 1/2" on the other. So something is way off if yours is right. Cause the longer one for me is the one that's distorting the entire front sheet metal
Posted via Mobile Device

[skip99]

take pictures with the support in the fender.. on mine, the holes line up easily,

[chevy49]

the larger one could be from a 1.5 ton or larger truck.just a thought.

[Dan Bowles]

I wouldn't have called that a core support but a fender brace. The core support holds the radiator. The support rods run from the firewall to the inside of the fenders. From your other posts elsewhere, I was measuring rods!

I have one of these off of a 1.5 ton and several from 1/2 tons. Tell me where you measure from to get the numbers you have and I can check.

[panelrodder81]

Ok so I did the swap today for my Champion Cooling aluminum radiator. The swap went perfectly fine and I didn't have any hood clearance problems as was suggested above. I had to make a big notch in the brace that ran over the top of the radiator and a couple notches in the core support in the bottom corners. Over all the swap was very simple and straight forward. So the short answer is that a Chevy rad WILL work in a GMC core support with minimal modification.

Here is a pic of the notch I made in the main cross bar:


Here is a pic of the front of the engine after the old rad was removed:

another of the empty core support:


Here are three photos of the rad in place before buttoning up the install:




I didn't take any pics after the final install of the cross bar before I had to hurry and drive home. I will try and take some photos of that tomorrow.

After I got the truck home my son wanted to stand on the driver's seat:


Hopefully this will help someone.

As for the comments about the fender braces that come off the core support, I think you either have one that is damaged or one from one of the larger trucks like was suggested above. Since there was a first hand account to refute my original opinion, I have adjusted and now find either of these to be the most likely.

-Panelrodder

[Dirty Doug]

I have a GMC front clip. I have a Chev and GMC core support, Chev hood, grille, top mounting / latch plate and the lower apron. Besides filling the turn signal light holes I cant see a problem. Am I missing something? Mine is apart but now I am wondering.