55.2-59 1955 2nd Series GMC Truck A/C

[Ocjason]

What A/C kits work best for this truck. I was thinking the Vintage Air kit (model# 941156), but some people are telling me it only fits Chevy. Is it only the controls in that kit won't fit GMC. Will the Gen IV evap unit fit under my dash? I would really like to stick with the Gen IV Evap. and not Gen II. Please help if you know...

Thanks

[mr48chev]

Why not check with Vintage Air directly? I'd say that the nay Sayers think that you have a GMC /Pontiac engine in the truck depending on six or 8 and the compressor brackets won't fit.
To me the "I've been told" or "they said" thing usually amounts to someone from the spit and whittle club throwing out nonsense or opinion. If the knowledgeable folks on here say that it won't fit the dash for some reason that is viable and they will also have and explanation.

I had a 57 GMC out here in the yard for three years and can't tell you a thing about the dash except I like it better than the dash in the 57 Chevy Panel I had in the 70's.

[burnin oil]

I am interested in this also. I have seen it said that it won't fit under the dash in a catalog. I am curious as to where the issue lies since I will probably be redoing my firewall as it is.

[_Ogre]

i did a combination of the surefit condenser/dryer/hardlines and a genII compac evaporator under dash unit. since the gmc core suport is different i'd just go with the genII compac setup on your gmc trucks.

the va surefit is old technology with cable operated air doors and heat valve, the compac unit is all servo drive for air doors and heat valve. you can also choose an under dash controller or 2 different in dash controllers

the pic below is how far it hangs down under the dash, it's quite a bit. i could have gone higher but since i shaved my glove box door i was concerned about serviceability. if you have a console getting floor hvac over to the drivers feet is a challenge. i ducted thru the console, works great. the dash fascia hides half the compac unit

[burnin oil]

Ogre
That appears to hang down about 6 inches. Am I correct? I would like to keep as much of the glove box as possible but tuck it up also. I am going with a factory dash other than instrument panel. I am going for the stock look with modernization so no custom looks or mods that are not needed.

[BBPanel]

For this project (56 Chevy Panel w/GMC dash) I decided to try Restomodair's Vapir 3 unit. The pics are showing the mock up unit (gutted - just a shell) so you can get the mounting bolts where you want them. The unit only attaches to the firewall. I've got about 2.5" standoff but it could have been as little as 1" or so. I didn't think to measure how far down it hangs but I'm sure its 6" or so. It could have gone up higher but the way I want to run the lines out of the upper kick panel lead me here.

[NWA58]

Old Air makes a direct fit kit for GMC but it hangs down significantly into the floor area and was too big for my liking. I’m still building but did a mix of parts from Vintage Air to use their universal Compac series evap under the dash and bought theIr condenser kit that fits the Chevy. My original GMC V8 core support is identical to the Chevy, so it was a direct fit. I fabricated brackets to hold the evaporator and it is a nice tight fit, but tucks up better than the boxy Old Air design.

[BBPanel]

Originally Posted by NWA58

.....My original GMC V8 core support is identical to the Chevy, so it was a direct fit.....

I don't understand this comment - here are the two radiator supports.

[_Ogre]

Originally Posted by burnin oil

Ogre
That appears to hang down about 6 inches. Am I correct? I would like to keep as much of the glove box as possible but tuck it up also. I am going with a factory dash other than instrument panel. I am going for the stock look with modernization so no custom looks or mods that are not needed.

6" is probably correct, the pass side fascia is 4" down. never an issue with leg room. your not going to have much of a glovebox after ac install. VA makes a 2" deep glovebox, you could make a custom box to slide in there out of fiberglass. well worth the work when it's 90° plus

[_Ogre]

Originally Posted by BBPanel

I don't understand this comment - here are the two radiator supports.

he may have a fleet option truck, it used chevy parts

[burnin oil]

Thanks ogre. I could care less about the AC but the better half is a different story. Honestly the truck will probably go no more than 2 hours from the house so I can open the window but I need to make her happy. The donor already has a Sanden compressor so I will add it for her once I begin the project. I already know that space is going to be an issue since I am cramming a 12v Cummins diesel in there so somewhere I need to make room as it is. My dream truck will be an adventure when started!

[NWA58]

I definitely have the Chevy style, the shorter one one the right in BB’s pic above. And it is not a fleet option. Mine is an original GMC with Deluxe Cab and V8, long bed. I planned to use a complete Mar-K short bed, so scrapped the entire long chassis (The motor was a locked up boat anchor anyway) and had TCI build me a new short wheelbase chassis. I was surprised when it showed up with a crossmember dip for the oversized core support you showed above, when mine matches the Chevy style. They had just built another GMC chassis for SEMA and assumed mine was the same. They fabricated new core mounts for me and were willing to build another chassis if that did not work, but everything is aligning well now.

[NWA58]

Here is the freshened original part

[NWA58]

Here is the original setup prior to deconstruction

[Ocjason]

When i talked to the guys at Vintage Air, they did not know if it was the controls or the Gen IV Evap was the thing the did not fit the GMC. I already know the Chevy Deluxe controls don't fit nicely in the GMC dash.

Underneath the dash width from the firewall to the bottom of the dash is 9.5" on my GMC (see attached pic). The diagram from VA for the Gen IV evap says it is 10.5" wide. That looks like the only issue. Can someone measure their Chevy dash and see if they actually have 10.5" I guess i could cut mine bigger.

The engine I am using is a LS based 2005 Truck Vortec. The V/A guy got me the correct condenser size for the GMC core support. It is actually way diff from the Chevy support as mentioned in the post above. I also got the correct Compressor bracket for LS engines.

I think i am leaning towards the Vintage Air Gen IV Evap unit unless someone gives me a hard no.

[NWA58]

Jason, you ran into the same thing I did, the GMC dash rolls under and there is less space to the firewall than the Chevy, so the VA SureFit for 55-59 Chevy will not fit. 9.5” hole for 10.5” evap means you either cut the dash or find a smaller underdash unit. The Vintage Air Compac fits nicely. Old Air makes a switch kit for the GMC dash, but it does not work with the VA.