Did you check your motor mounts?
You'll get more answers if you post this in the right section. Go to the 1979-1995 GT section or the specialty cars section for Saleens, etc.
chevy runs deep, Don't step in chevy!
289 - Holley 4150 570cfm; Performer intake; mild cam; MSD HEI; 302 heads; Roller Tips; Hedman Tri-Y headers; H-pipe w/Flowmaster 40's; 9 in posi 3.50; 205/50-17F; 225/50-17R.