1978 A/C Question

Z-28 Roadracer

New Member
Aug 23, 2014
Winneconne, WI
Hi everyone, first post here. I've been looking around here a little before I signed up and it looks like there is a great depth of knowledge on this site.

The question: Is an A/C assembly from a '79 the same as the unit from a '78?

The long story:

My wife has a '78 Z-28 that she bought from a friend who modified it to be better suited for autocross several years ago (urethane suspension rebuild, stiff springs, gas shocks, sub-frame connectors, 4 point roll bar, WS6 sway bars and disc brake rear, 16" wheels).

One of the mods was that he removed the A/C, blocked off the firewall with an aluminum plate and mounted the standard heater parts to the plate. Most of the non-A/C ducting appears to be there but when he mounted the heater assembly to the inside of the firewall, he missed on the lining up the housing inside with the core and outer housing so there is a gap that lets hot air through all the time. He did add the non-A/C kick panels and cut holes for the air to flow through from the cowl.

I found an A/C assembly cheap (firewall assembly and most of the ducting) and am considering reinstalling A/C in her car so that it doesn't blow hot and (after we swap the 350 for the 496 waiting to be built) putting A/C back in it.

I know the dash changed between '78 & '79, did the ducting change as well? Are the firewall boxes interchangeable between those years? Is it worth it or should I just fix what I've got and roll down the windows?

For what it's worth, my wife says "It's a racecar, it shouldn't have A/C" but the parts are almost free...


Veteran Member
Jan 21, 2013
I personally would go with a aftermarket A/C like Vintage Air. A lot easier to install than trying to get those old systems back up & running.


Veteran Member
Jul 25, 2014
Huntsville, Texas
If it's almost free, why not just get it and try? The main components should be the same and what little differences there are, maybe between what you already have and what that comes with you can coax it together.

Love the wife's attitude too. Mine wants to know why there's no vanity mirror in the visor.


Veteran Member
Feb 11, 2008
Olney, MD
There must be some differences between '78 & '79 but I'm not sure what they are.
Vintage Air has diffferent systems for the two years and Classic Air has a diirect fit system for '78 but not for '79.


Veteran Member
Jan 31, 2000
Nanaimo, B.C., Canada
I believe the 78's were that last year for TXV type freon flow control; 1979 was the first year for the CCOT system. If that's the case, the evaporator outlets will be different. If you can grab everything off the '79, it will be a bolt on, other that the '78 center vent and associated ductwork.