47-55.1 GMC vs Chevy radiator differences/depth

[weim55]

Putting together details on an engine swap for my ‘50 3600 . It’s looking like I may need an inch or two additional clearance between the engine and the radiator. I believe the GMC’s had a slightly longer engine than the 216, does the GMC have a different radiator placement in the same radiator support as the Chevy, or is the radiator support different?

Steve weim55 Colorado

[jweb]

The supports are different. I believe the GMC was designed to tuck into the support, you can see a different style neck on the GMC radiator in the link.

Radiator
https://www.ebay.com/itm/225598101800

GMC Support
https://www.ebay.com/itm/12570818294...CABEgIbpPD_BwE


Chevy Support
https://www.ebay.com/itm/22594647291...CABEgK5LPD_BwE

[mr48chev]

Looking at my aluminum radiator for my 48 I'd think that the GMC radiator will get you about an inch of space. You may have to modify the cross brace on the radiator support to clear the tank though.


Chevy radiator support that is several times better than the one that guy wants 222 for but I would be ashamed to ask 20 bucks for as I don't think it is up to par.

[mr48chev]

If you go too far forward you have to do something with the cross brace and panel in front of the radiator

Yellow shows the radiator sitting forward in the core support

Middle one is GMC Making me think I can use my GMC radiator support with the cross piece of a Chevy radiator support or a custom cross piece.

The blue one is the radiator in the stock position in the Chevy radiator support, note the piece in front of the radiator to block air from rising up and over the radiator. That shows how much space you have available.

[mr48chev]

On the yellow truck they removed a good portion of that top piece on the radiator support and probably used GMC brackets but you don't notice it unless you know what you are looking at and that should be real close to the difference between the GMC and Chevy bracket mounts.

[jweb]

Originally Posted by mr48chev

On the yellow truck they removed a good portion of that top piece on the radiator support and probably used GMC brackets but you don't notice it unless you know what you are looking at and that should be real close to the difference between the GMC and Chevy bracket mounts.

Mine is similar to the yellow truck. I cut the top of the radiator support and mounted the radiator inside of the support, using spacers to push it as far forward as I could.

I should have started with this or made a nice piece to finish off the top.
https://www.streetrodhq.com/detail/1...pport_Kit.html

[dsraven]

on my Canadian 57 I built a new rad support to fit the new rad, a/c etc further forward. if you cut the top off to fit the rad further forward you can fab up a brace to keep it from squeezing the rad when things flex etc. trim stuff to fit, then build around that.
you got this.

[dsraven]

my version of the rad support for the task force truck. the '04 gmc envoy rad fits inside it along with the a/c condensor. I haven't got the hood latch started yet but it's another thing to consider.

[dsraven]

jweb, nice clean looking unit you have. great job.

[Klorne]

Anyone's rad support look like this? Looks bent.

[dsraven]

looks a little suspect alright. maybe an accident victim?

[mr48chev]

We have a tighter space to move things on AD trucks. Plus we can't hide what we did as well as you did with your TF.

After looking at several of my photos taken over the years I'd say that running the GMC radiator and trimming the piece that runs across the top of the radiator support on the Chevy as done on the yellow truck is the simplest way to get an inch of space.

In a photo from the left side on the yellow truck they did go old school and slide the radiator down inside the radiator support. It looks like they also set it an inch or so lower.

If I can ever catch up with him I need to talk to my buddy about cutting the brackets off of mine and moving them back per GMC. That would be a 30 minute project for him


I don't have more photos of the Chopped Blue truck with the cross flow in it but it looks like they put some thought into it and did some nice fabricating.

[Klorne]

It's weird, looks like a clean bend not twisted or banged up. Looks like it's supposed to be like that. Of course it is old and crusty, but other than that it lines up with the fender and crossmember holes just fine. Its on a Canadian GMC, maybe that's why?

[mr48chev]

Originally Posted by Klorne

Anyone's rad support look like this? Looks bent.

That should be GMC if it looks Like the one on the right.

Chevy on the left


That fits the front two holes in this crossmember

The Chevy crossmember being quite a bit different. URL=https://hosting.photobucket.com/images/w71/mr48chev/Screenshot_(480).png?width=960&height=720&fit=bounds][/URL]

[dsraven]

good ole mr48, always comes through with the goods on AD trucks. could prolly write a manual.

[leegreen]

is the one that looks bent from a 1.5+ ton 'big' truck? Their fenders and hood are longer, maybe the bend kicks rad forward from crossmember. If it is from big truck it will be too tall for 1/2 ton I think.

[mr48chev]

Originally Posted by leegreen

is the one that looks bent from a 1.5+ ton 'big' truck? Their fenders and hood are longer, maybe the bend kicks rad forward from crossmember. If it is from big truck it will be too tall for 1/2 ton I think.

That could be. I've got a couple out back but don't know If I am up to fighting my way through the weeds and snow.

[Klorne]

I apologize, I didn't mean to take over this thread. I started another one the other day, but no replies on it so far.
So apparently the Canadian GMC's used the Chevy rad support. Seems strange that it lines up with the crossmember and the fenders. It's like the crossmember is set back 3/4". I'll have to take some more pics and add them to the other thread.

[Klorne]

I have an extra rad support from a big truck, and yeah, it's a couple of inches taller.