What material were the vendors selling for the top tack strips for open cars? It was some kind of plastic---Nylon. Polypro. or what? It does not appear in the recent catalogs I have. The stuff I saw was white and could be shaped with heat and held nails well.

It's called white oak.

The Cubels carry the synthetic tack strip material.

http://www.fordwood.com/

I bought the tack strip from Cubels and it worked great. I used it on the tack strip on the front and back seat. The top or the upohstery can be attached in no time. I used a propane torch to heat the strip as I applied it and used spring clamps and c clamps, and whenit cooled it stayed there.
Good Luck.

Brendan:

Many, many years back one of the guys in a T club that I was in went to Denver to a plastic factory and bought a large sheet of soft plastic. The place told him that it was a batch that had come out bad and they were glad to get rid of it. It was an inch thick so it was cut in strips and some of us used it for tack strips. It worked great and is still holding tacks.
When I bought my Montana 500 roadster I tore it completly apart, put in a different motor, rear end, frame and upholstery. When I removed the upholstery the tack strip was a tractor belt. The tacks were holding good so I did not replace it. The fan belt was just the right shape. It was about 1 inch on the inside and about 3/4 inch on the outside. The tacks held good for a number of years but then I installed murphey fastners all the way around so I can remove it during the race. I also remove it when I am trailoring it.
If I can not find some plastic when I upholster the next Car I think I may look out back of some of the tractor places and see if I can get another belt.

I meant to say I remove the top during the race and when I am trailoring the racer. With murphey fastners all the way around it does not take any time at all to remove the top.