71/72 air cab question

[CG]

im talking just the metal here....is the only diff between an air cab and a non air the vent outlet holes in the dash? or is there something diff on firewall too?

[WRMZ71]

Yes the firewall setup is different inorder to accomodate for the different heater box and such.

[4x4Poet]

How, exactly, is the firewall is different?

[72 CustomCamper]

Here's a pic I have of the difference...

Chuck

[4x4Poet]

Rats! I was hoping to install a '72's A/C system on my '71 K10. Already have the condensor, evap, outer/inner housing, vents, etc. Just need a compressor, dryer, & hoses, basically.

Is the above difference resolvable by welding up the large hole and cutting new or by cutting out just the different part from a wrecked '72 cab and patch-panel welding it in? Any other differences, such as how much the firewall sets out from the cab?

And thanks for the clear pic, 72 CustomCamper.

[Gee_Emm]

On my Jimmy I just welded up the one hole then cut the new hole. I didnt go to the trouble of rounding over the edges like the original hole had since the whole thing will get covered up by the air box. You will also have to weld up some of the little holes and drill some new ones, there are dimples on the firewall where the holes are supposed to be so that part is easy.

It would greatly help if you could have another AC truck right there to transfer the dimensions from. Another way to get the correct size and placement of the holes is to take a big sheet of white paper to the junkyard, find a AC truck, lay the paper on the firewall and with your dirty hand rub out the outlines of the holes, make sure to get a few reference marks rubbed on so you know where to place the paper on the cab when you get back home. The same trick can be used for the inside vents.

[mrein3]

Originally Posted by Gee_Emm

On my Jimmy I just welded up the one hole then cut the new hole. I didnt go to the trouble of rounding over the edges like the original hole had since the whole thing will get covered up by the air box. You will also have to weld up some of the little holes and drill some new ones, there are dimples on the firewall where the holes are supposed to be so that part is easy.

It would greatly help if you could have another AC truck right there to transfer the dimensions from. Another way to get the correct size and placement of the holes is to take a big sheet of white paper to the junkyard, find a AC truck, lay the paper on the firewall and with your dirty hand rub out the outlines of the holes, make sure to get a few reference marks rubbed on so you know where to place the paper on the cab when you get back home. The same trick can be used for the inside vents.

Actually he does have a template for the dash mods because he said he has the evaporator housing.

Look at the picture posted above showing the differences the two firewalls. The pictures used to make it weren't lined up perfectly. In reality the red non AC hole in the firewall and the yellow lower heater hose hole in the AC firewall line up. The dimple is there to cut the upper hole.

Using the factory assembly manual I made the other hole in the non AC firewall first.

Using those two holes as a guide make a trace of your non AC firewall.

Then take your AC evaorator box again using the two AC equipped truck's heater core holes and make another trace.

Now with the two templates use the heater core holes to line them up. Remember they face each other so you have to make sure you line them up the way they exist on the truck.

Make a paper template of the piece of sheetmetal you need to cut out.

Test the fit on the truck then make the metal cut out.

Test the fit. Weld it in.

Done.

[4x4Poet]

Great info all around. Thanks a lot, all of you.

[Dano69c10]

This may sound crazy, but I have an A/C cab that I want to turn into a non A/C cab. I just use my truck for Home Depot runs and to work 10 miles a day.

Can someone make me a template of the non A/C holes on the same template? I have a non A/C heater boxes inside and out that I would like to install.

Thanx
Dano

[Dano69c10]

ttt

[avejoe]

Can just the heater portion of an ac system be installed on an ac cab?

[Dano69c10]

Unfortunately I don't have any of the A/C equipment, just the non A/C boxes dutcs, cables and control.
Dano