One of my best car buddy races his 69 Camaro in the Vintage class at Sebring. The car has been extensively modified and is now a "race only" car and he consistently runs mid to upper pack using a tired 302. The car should be even faster when he finishes building his 350. He is using his stock subframe, stock upper and lower arms, and stock steering box with solid body mounts and firmer springs. The major modifications are the Goldstrand conversion and he tweeked the steering arms to eliminate bump steer. When he really got serious he stiffened the whole car by adding a full roll cage that extends through the firewall and is welded to the front of the frame rails and is cross braced between the frame rails behind the radiator. His latest modification was to add a NASCAR style sway bar. In the back he's running multi-leaf springs and a panhard bar. Sweet setup.
By the way, we've visited with Stacy Tucker of DSE the last couple of years at the Turkey Rod Run in Daytona and she really knows her stuff. He has picked her brain about various topics and she was instrumental in helping his maximize the rim sizes to use so he could squeeze more rubber under in the front of the car. I asked her father if he had any more like her at home. She's every car-guy's dream girl.