New Member with 70 Z28 RS

Jan 9, 2022
New Zealand
Those little details take time to fix and finish but sure worth it in the end. Hope that's the only hack job like that on the car, hate to see that stuff on a upper level car.
Totally Tom3 it's satisfying work.
I have to do rust repairs to both the lower parts of the A Pillar and cowl is rusted in that area.
I've got a new cowl but hope to use just the ends and keep as much of original sheet metal as possible.




Staff member
Lifetime Gold Member
Feb 7, 2006
Hi All

Sorry for the delay getting back about the A/C unit.
I think I might start a build thread if there is enough interest.
This is what I found after removing the A/C unit.
2 VIN numbers one under the heater fan and the other under the heater box, both the same as VIN tag on cowl and build sheet.
The hole cut to fit the A/C unit looked bad but on closer inspection were easily repairable.
I was happy to find the remaining folded edge were left intact and just flattened, so I was able to bend back and fill in the gaps with fresh steel.
I bought a std heater unit which has helped a lot.
There is a hole center for some wiring which looks awful, like someone took to it with an axe.
See below photos of the damage and repair.

Cheers Chris

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That was a lot of work to do a half a$$ed job on retrofitting AC to that Z...unbelievable that someone would go to the trouble. Thanks a bunch for posting back up and letting us know what you found.


Veteran Member
Aug 1, 1999
I think that A-pillar rust is from the firewall/cowl to body seam that is poorly sealed and actually sits in a depression. Over time the water that lays in the low spot gets wicked up through the seam and keeps that corner wet under the dash sheet metal. Usually seems to be worse on the driver's side probably due to the driver's door being opened and slammed shut much more than the other side. Little detail sure makes a big mess to fix in that spot.


Veteran Member
Oct 3, 2013
SK, Canada
I'm glad you posted those pics. Slightly off topic, but when I bought a '74z28 parts car for the one I was fixing up, as the parts car had AC I toyed with putting the factory system into my non AC car. As that was long before internet and blog sites like this, I had to read up on what I could. Glad I did as I certainly changed my mind when I figured out the firewall differences on top of the complexities under the dash. I had that all apart on the parts car before I started any massacre of my "good" car.

And congrats on "getting to the bottom of" your "AC in a '70z28" mystery.