[Dwight]

I'm having my GT 40 body painted. When talking to the owner of the paint shop, whom I've know over ten years, he said we need to prime/seal the bottom of the fiberglass.
Tommy was a PPG rep for 15 years before he opened his own body shop. I think he knows a little about paints, putty, sealers, clear coats, etc.
I had a fiberglass Cobra for 18 years and it had star cracks on the rear fender. I thought they were from rocks thrown up from the tires. Several years later I got under the fender to check the cracks out. There was no way a rock could have caused the chip. The area under the chip was closed up with fiberglass panels (inter fender panels).
As Tommy and I were talking about sealing the bottom he explained that water can soak into the fiberglass and cause the prime/ paint to turn loose. Causing what looks like chips and cracks.
After what I've seen on several Cobras through the years it's easy for me to believe what Tommy is telling me. Never seen a Cobra with the bottom / backside primed or sealed.
He is going to seal all the back side of the body and then most of it will get a bed liner coat.

My Cobra had a stress crack on the hood at the edge of the scoop.

Lots of rock chips on the front. Not a fiberglass problem, just lots of high way miles.

Maybe some of the Vette guys can chime in with their experience.