Book on Trans-Am Cars

[Steve Holmes]

Acid dipping was pretty common in the Trans-Am, particularly by the factory teams. Dan Gurneys All American Racers team built both the factory Plymouth Cuda's which they'd be racing themselves, plus the Dodge Challengers that the Autodynamics team would race. Apparently the Challengers were left in the acid too long, and the shells became very weak, which was to affect them throughout the season, as the shells kept sagging.

[Steve Holmes]

Just one theory (from Car Life Mag in 1970). I'll leave it to the experts to argue its validity:
The forward part of a car roof is a negative pressure area. Venting the higher pressure cockpit air into that area would noticeably reduce lift. With a vinyl skin covering a series of pin holes, this could have been accomplished without the inspectors noticing (they tested the car with magnets). Nobody ever figured exactly why they ran the vinyl, though and finally got them off on a technicality. (The roofs didn't appear on the homologation papers.) The rules didn't say Penske couldn't use them, so his record was safe.

According to Mark Donohue's book, The Unfair Advantage, the vinyl covers were put on the '69 Camaros because the bodies had been left in the acid bath too long to try and get as much weight out of them as possible. The roofs became quite badly dimpled. Also, according to Donohue, because the team repainted the cars usually after every race, by not having to paint the roofs saved them money. I can only assume this is true, as he is quite open about everything the team did to gain an advantage.

[Ellis]

A story in one of the TA books I read...
(a) Tech Inspector having a beer with one of the teams after the races leant on the roof of a race car.
Said something like .." You fellas have a bit of work to do before the next meeting"

(b) May have been Dan Gurney testing a car a day before a meeting on a hi speed track and the roof
was bending in and touching his helmet from air pressure. He asked them to cut the roof off and replace it
with a standard one which they removed from a car at a dealership.