I just placed my first order after comparing a few places and went with Classic Industries. I was looking mainly for rusted out floor parts and they had 25% off for another week or so. I should get my order Wed & can tell you if I made a good choice or not, but the salesman told me it was 16-17 gauge steel.
Here's my thread & folks input:
http://67-72chevytrucks.com/vboard/s...d.php?t=771563
If you find a good car rebuild kit, let me know from where. That project is coming up soon.
Good luck