We spent many years racing a Chevelle and spent thousands of dollars. Only one system your will effectively work with these cars on small tires. You may have heard of the weibe suspension well ours built upon this system and improved some features.
Our 67 was 3850 and I'm 200 pounds. Car went 1.28 60ft with the rear wheels, 555ci 13.1 ALL motor engine. Stock 12 bolt with 3.73 gears on radial slicks. Car was like a zerox machine for 60ft times.
I build and sell these suspensions. Get in touch with me if interested. You will be much further ahead in the long run.
Here is our car.
https://photos.app.goo.gl/BNzy7MpMfawgBzZ96