67-72 Non-Factory A/C Conversion to Factory A/C Firewall Questions????

[kna4977]

Do you have to have a donor firewall to make the factory A/C work? If not, do you have to weld in a piece of metal to fill in the existing hole and then cut out for the factory A/C firewall hole, or can you modify the existing one????? If so, what is the best way to modify it?

thanks

[PICKMUP]

I have done several and the AC box will go on the firewall and cover the non-AC big holes and function just fine...no need to weld in the slightly larger AC holes.
When you set the AC box up to the firewall it will show you where to drill the little holes for the bolts around the box.
From there you just install everything like the original.
Here's one I have been driving for years...still blows cold...never cut or welded the firewall and didn't even pull the dash.

[sneakysnake]

Here are the differences

[kna4977]

Originally Posted by PICKMUP

I have done several and the AC box will go on the firewall and cover the non-AC big holes and function just fine...no need to weld in the slightly larger AC holes.
When you set the AC box up to the firewall it will show you where to drill the little holes for the bolts around the box.
From there you just install everything like the original.
Here's one I have been driving for years...still blows cold...never cut or welded the firewall and didn't even pull the dash.

Do you need to cut anything out then besides the round holes??

[gregbr]

pickmup, Do you have to install the 2 dampers....inside cab on vent damper and under the hood in the cowl??? I trying to decide on factory or aftermarket a/c on a non a/c factory bigblock numbers matching shortbed. Any info or thoughts would be great. Thanks, Greg

[kna4977]

Originally Posted by gregbr

pickmup, Do you have to install the 2 dampers....inside cab on vent damper and under the hood in the cowl??? I trying to decide on factory or aftermarket a/c on a non a/c factory bigblock numbers matching shortbed. Any info or thoughts would be great. Thanks, Greg

I've been told that you don't really need the one from inside the cab, and that it never worked all that well anyway

[kna4977]

Originally Posted by gregbr

pickmup, Do you have to install the 2 dampers....inside cab on vent damper and under the hood in the cowl??? I trying to decide on factory or aftermarket a/c on a non a/c factory bigblock numbers matching shortbed. Any info or thoughts would be great. Thanks, Greg

If you are a guy that really likes the look of the original system, and don't mind a little hard work, go original. If you don't care about the look and want something that is functional, costs a little more, and is easier to install, go aftermarket.