How effective are the under dash AC duct outlets on a original car?

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DionR

DionR

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Been ruminating on how/where to put AC vents in/on my dash. Noticed that it seems like the typical format for most cars is two in the center of the dash and one at each corner. This puts them fairly high and you can get air from both sides.

I'm curious how the effectiveness of the under dash vent setup on original AC cars compares. Does it seem like it still cools the occupants as well, or well enough? Any loss having the vents lower under the dash rather than up high towards the top of the dash? How about not having a vent on both sides?

Thought about putting 2 vents in the middle of a junk Rallye dash where the radio would be, plus one in the corner next to the speedometer. But not sure where to put the one on the other end of the dash. And if the under dash vents work ok then I'd rather that option and keep it looking somewhat stock even if a '74 never came with a Rallye dash.

Thanks.
 
I have the knee knocker hanging from the dash in the passenger side on both of my mopar's and with 23,000 BTUs everybody's trying to get it not to point at them...lol ..
 
My factory ac in my 69 Cuda with the three vents in the center will freeze you out. Probably not the best design, but very functional.
 
My dealer installed system in the '65 Dart easily keeps up with 100+ temperatures, but I can definitely run into overheating my left arm and making the shift lever too cold to touch. Spreading out the BTUs would be beneficial, but I plan to leave it as is for appearance and simplicity.
 
The problem with putting vents in the dash is, there's no room to run the duct hoses back there! It's tough enough just trying to snake the defrost ducts into place- imagine trying to fit in another 2-3 hoses. The factory underdash vents work pretty good, they're fairly wide and the individual vents can be directed to distribute the air pretty well; the dealer installed and aftermarket knee-knockers are pretty localized, but they are what they are.
 
I had a knee knocker in my 66 dart back in the day. Worked good, & you could pour your warm drink down the vent & it would exit through the drain in the unit. Not that I ever did that….
 
Professor Fate said:
The problem with putting vents in the dash is, there's no room to run the duct hoses back there! It's tough enough just trying to snake the defrost ducts into place- imagine trying to fit in another 2-3 hoses.
Click to expand...

Hadn't thought about the hoses. Since the center ones would replace the radio, I would guess those would be ok, and the passenger side one shouldn't be hard. But I could see the left DS one being a real pain.
 
If you really need some outboard vents, you might be able to tuck some smaller diameter hoses along the underside of the dash and use some underdash vents like these from Classic Auto Air at the dash ends. Just tap the hoses into the factory center vent. That way you could avoid trying to fit hoses around the instrument cluster, radio, HVAC controls, wiper linkage, and glove box.
A/C Vents | Classic Auto Air - Air Conditioning & Heating for 70’s & Older Cars & Trucks.
 
My 70 440-6 had add-on "knee knocker" and it just worked great. The vent diffusers are adjustable which helps a lot
 
Professor Fate said:
If you really need some outboard vents, you might be able to tuck some smaller diameter hoses along the underside of the dash and use some underdash vents like these from Classic Auto Air at the dash ends. Just tap the hoses into the factory center vent. That way you could avoid trying to fit hoses around the instrument cluster, radio, HVAC controls, wiper linkage, and glove box.
A/C Vents | Classic Auto Air - Air Conditioning & Heating for 70’s & Older Cars & Trucks.
Click to expand...

Those are what I am really trying to avoid. If I was going to do something custom, I want it to look somewhat integrated, and those to me look too....JC Whitney? I like the stock look because it is stock, but would want custom ones to look like maybe the factory could have done it that way.

I plan to do some home engineering on the whole thing anyway and am going to try and use a Ram heat/ac box. I know it will probably be visible under the dash if you look, but I like the idea of using the stock under dash vents as long as they work ok since it is simple and looks factory as long as you don't look too deep. If the stock vents didn't work well then I would go looking for ways to integrate vents into the dash. Based on the input here, I'm leaning towards just using the stock piece and see if I can get it connected and working.

I wish Mopar had done vents like the Chargers and such. But they didn't.
 
The 66 Coronet ( and maybe the Charger and Plymouth B Bodies as well) had these separate outer dash vents that mounted under the dash and had defroster dtule hoses that connected to the AC unit. I forget where the center vent was installed. I’ll dig these out tomorrow and take a couple if pictures.
 
65 Dartman said:
The 66 Coronet ( and maybe the Charger and Plymouth B Bodies as well) had these separate outer dash vents that mounted under the dash and had defroster dtule hoses that connected to the AC unit. I forget where the center vent was installed. I’ll dig these out tomorrow and take a couple if pictures.
Click to expand...

Pretty sure the 69 or 70 B-Body had at least the center vents in the dash. But not sure on the end ones.

Edit - Appreciate the input, curious to see how those parts look.
 
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