(VIDEO) Suspension HELP for 70 dart swinger drag racing!

[YT][/YT]
Hey guys, looking for some help with the suspension on my 1970 dodge dart swinger. Car has a 340 with around 450-500 hp, powerglide transmission with transbrake (leaving around 4000). In the front I have new qa1 control arms with 90/10 shocks and mopar performance torsion bars, The car has good free travel of 5+ plus in the front. Going to the back I have the subframes connected, calvert mono leaf, caltracs, qa1 single adjustable shocks. The car has also been minitubbed with leafs relocated allowing me to run 28x11.5x15 MT ET Drag slicks. I ran last weekend at a local 8th mile strip, best run was 7.23 at 93.3mph with a 1.58 60', but cant get the car to leave the line without spinning. Tried caltracs in both top and bottom hole, preload and no preload on both, shocks set all the way loose in the back, tried tire pressure from 9.5 all the way to 13.5(ordered tubes to help stiffen sidewall of slicks now). Any suggestions are greatly appreciated! Thanks, Cole.