Here are the differences between an OEM A/C and a non-A/C a-body:
1. The firewall has a bigger cut-out for the fan motor on A/C cars...not a problem, just make an adapter ring out of sheet metal or sheet aluminum.
2. Dash controls are different......use and electronic controller or find a non-A/C controler.
So, if you are mechanically inclined enough to install an entire HVAC system you can take care of the small stuff yourself. As you can see, even the "custom fit" unit needed some work.
