My 70 Malibu build

[Quadracer392]

What is that? Looks like the jute padding that goes under the carpet.

Haven't done much last few days because I was out of town all weekend, but I did get my other frame back today and it's in pretty awesome shape. It doesn't have very much rust on it at all and since I'm not powder coating it. I'm wondering if I should have it blasted or just use a wire wheel and clean it up real nice? Just goofing off tonight using the drill and wire brush I hit it in a few spots and got it to bare metal rather easily. What have you guys that have done this before, done to your frames?