If memory serves me correct, the old Chevy frames are 10ga., just a bit under 1/8"... I'm a big fan of the Independent Front Suspension, others here prefer the look of an I-beam like the original. Either way can give you a quality disk brake system, discs on the rear are easy, too. I like a narrowed 9" Ford on the rear with coil-over suspension and triangulated 4 bar, others have gone to the 3 link rear to free up a bit of space for exhaust over the housing.

Best advice I could offer is to sit down and decide the look, or "theme" you want on the car, then plan carefully to purchase the parts that will compliment your central theme. The more time spent planning things out leaves fewer surprises during the course of the build.

And, 2 rules that hold true on every project;
1. It's going to take longer then you thought
2. It's going to cost more then you thought