The F-body is the Camaro Firebird and Teans Am (any year) and they are an oddly heavy car with poor frame strength.
The G-body is the 78-87 Malibu, El Camino, Monte Carlo, Regal, Grand National, Cutlass, Bonneville, 442. I think that's all of them. They are lighter than the F-body and stiffer than the F-body and the previous deacades A-Body. They already come with front disc brakes and can be had with the optional F-41 suspension package wich came with a stiffer front sway bar, a rear sway bar and Radiator core support to frame stiffeners. There are a lot of companies making stiffening parts for the G-body to make it even stiffer. Also, most people don't know that the El Camino actually has the best weight balance of all the cars mentioned above. It can be made to a perfect weight balance without a lot of effort and a little fiberglass.
If you are planning to make a drag car without a ton of cash, a G-body can be had for real cheap in good shape when compared to a similar F-Body.