I will ask for any advice. 3,138 lbs car with driver. weight bias 48.6% on rear wheels, 120 lb rear springs, double adjustable shocks all four corners, anti squat set at 116% instant center length 68 inches 14 inches height. Car ran last year 6.0 @ 114 mph in the 1/8 with the converter slipping. Shift light never went off the entire run after launch. New converter problem fixed. Car leaves perfect, lifts the wheels about a foot and carries them out a little way. 1.35 60 foot, the Issue is the car wants to spin the tires at the end of the 1/8 mile. Tires are a couple years old but have lots of meat on them. The four link was put under the car 20 years ago. I am thinking for maintance the heim joints need replacing. Everything appears tight no cracks in brackets. My main question is would a longer lower instant center help plant the tires down track? Any other ideas on fixing the problem of breaking the tires loose down track? Engine makes 800HP and about 750 ft. lbs of torque.