Custom Heater & AC housing

[Mutt's37Buick]

Has anyone ever custom built a Heater & AC housing for under the dash?
I have a complete evaporator & heater unit from a '95 Roadmaster, but it is too large to fit under in my '37 Roadmaster dash. Thought I may be able to fab a smaller housing that can be used with the heater core, evaporator and blower. Fewer controls, but custom made to fit under my dash.
1) Has anyone done this, and how did it turn out?
2) What material would you recommend for the housing?
Pictures would be great.
Thanks
Mutt

[lamin8r]

Has anyone ever custom built a Heater & AC housing for under the dash?
I have a complete evaporator & heater unit from a '95 Roadmaster, but it is too large to fit under in my '37 Roadmaster dash. Thought I may be able to fab a smaller housing that can be used with the heater core, evaporator and blower. Fewer controls, but custom made to fit under my dash.
1) Has anyone done this, and how did it turn out?
2) What material would you recommend for the housing?
Pictures would be great.
Thanks
Mutt

Mutt,why dont you just look at a Toyota Hi lux pickup heater,etc..The Japs have some nice small heaters in their cars/trucks,,and I know a guy who has used the Toyota unit before..They are quite small..

[sunsetdart]

Mutt................I have a buddy who fabbed duct work out of fiberglass to make defrosters for his 33 coupe. It took lots of hours but what you want to do will be really long hours.
I agree with lamin8r and using something from a smaller vehicle. No need to try to reinvent the wheel.

[rspears]

If I were going to tackle it I would use the green florist foam blocks and a hot glue gun to form the shape of the box to fit the space, considering the positions of the evaporator and heater core; then saw it in half so you can mold seperate halves with flanges to bolt together. Set the halves on a slick surface, wax for release and glass the foam. Clean out the foam, and you have the hollow box and can glass in brackets, angles, etc to hold pieces/parts. Lots of work, but it should work OK if you know enough to position things right.

[Mike P]

I’ve been following your posts on this subject both here and on Hotrodders.com and sunsetdart pretty much hit it on the head.

“.......Mutt................I have a buddy who fabbed duct work out of fiberglass to make defrosters for his 33 coupe. It took lots of hours but what you want to do will be really long hours.

I agree with lamin8r and using something from a smaller vehicle. No need to try to reinvent the wheel.......”

It’s not only just building the box to hold the components and fit under the dash but also the internal doors to change from heat to defrost and AC. Then there will also be choosing dash vents that will complement or at least not look too out of place in the car.

Obviously cost is a factor for you otherwise you’d just order and aftermarket unit and be done with it.


For what it’s worth, if I were building this car and planning on leaving the dash fairly stock, I’d be looking for a vintage 50’s-60s under the dash add on AC unit. Personally I would be all over something like this to restore and (and leave/rebuild the stock heater).

Vintage Original Under Dash AIR CONDITIONER FORD-CHEVROLET-DODGE-Car-Truck-Bus | eBay

[Dave Severson]

There is an alternative....After doing a number of these fat fendered, skinny cowl cars if I ever do another one the A/C and heater components are going to be a rear mounted unit. Space under the dash gets to be at a premium with just the electronics and electrical stuff it takes to run an EFI engine. Vintage Air sells one, getting it for my '57...or get a rear AC and heat unit out of a van......

[Mutt's37Buick]

Thanks everyone for all your advice.
I put this question out there because I figured there were other paths than aftermarket.
You given me some reasonable options.
1) If I were to go the rear air route, would it be difficult to mount the HVAC unit out of the 1995 Roadmaster in the trunk, instead of buying another rear one from a van? Probably overkill, but I do already have it.
2) There also seems that there is a lot of room under the floor, has anyone mounted a unit under the floor and duct all the way up to the dash for defrost, or would the unit not work well outside the cab area?
Thanks
Mutt

[NTFDAY]

The evaporator should be in the cabin, but with good duct work it'd probably work in the trunk. Where ever it's mounted there has to be a drain to the out side.

[Mutt's37Buick]

It's a long shot, but do you know if it is possible to duct heat from the trunk to defrost the front windshield?
Thanks
Mutt

[rspears]

It's a long shot, but do you know if it is possible to duct heat from the trunk to defrost the front windshield?
Thanks
Mutt

Some of the earliest ac units, by Chrysler I believe, were trunk mounted with clear plastic "horns" on the package tray to direct the air flow forward in the cabin. They quickly moved the evaporator under the dash for improved performance. Here's a modern unit built around that same concept - Classic Auto Air - Air Conditioning & Heating for 70’s & Older Cars & Trucks.

[Mutt's37Buick]

1) Do you know if it would be possible to convert the stock 37 Heater to 12 volt and use it primarily for defrosting windshield. A trunk mounted unit could then be used for defrost rear glass, cab heat, and cab AC.
2) How would I extend the compressor lines for my '95 AC all the trunk?
Thanks
Mutt

[rspears]

1) Do you know if it would be possible to convert the stock 37 Heater to 12 volt and use it primarily for defrosting windshield. A trunk mounted unit could then be used for defrost rear glass, cab heat, and cab AC.
2) How would I extend the compressor lines for my '95 AC all the trunk?
Thanks
Mutt

Mutt,
On cars with AC the defrost setting runs the compressor to dehumidify the air while adding heat, clearing fog about ten times faster than heat alone. Seems to me you're making a lot more work for yourself, but I expect converting your stock heater to 12V is nothing more than changing out the fan motor, or installing an in-line resistor to drop the voltage to the fan to 6V (I'd replace the motor and run it at 12V).
On the compressor lines, you just have new long lines made up with the necessary fittings on each end to mate to your compressor and evaporator. You're also going to be extending your heater supply and return hoses the length of the cabin, too.

[Mutt's37Buick]

Thanks for your help

[Mutt's37Buick]

If I use a trunk mounted ac & heater unit, I may be able to run a defrost line from the rear into the front stock heater.
Can someone tell me:
1) When rear heat is used on a vehicle with front heat does the outlet from the front heater core feed into the rear core or is there some method of running in parallel?
2) What is the longest ventilation duct anyone has seen coming off a a rear a/c unit and how large was the duct?
Thanks

[Mutt's37Buick]

1) Can any one tell me if the "air intake" for the Vintage air Gen 2 Super Heat/Cool unit is hooked to an outside vent. I could not see anything in the install instructions.
2) Is the the cowl vent usually closed off when Vintage Air or other aftermarket air is added?
Thanks
Mutt