Help on 340 combo

i am running a bg 280 pump with 1/2 in line 5 gal fuel cell, the msd distrebuter is set to go full advace at 2500 rpm i am shifting at 6000 rpm. mph is off and the car is slow of the line even with the trans brake... one thing i just found is that the pinione snuber rubber is smashed off and the pad it hits is bent up almost 2 in. also the rear leaf springs are starting to twist and sepperate. i come of the transbrake at 4000 rpm looked at a vid of the car and the rear end drops real low and the front end comes up hard befor it really move forwards. the motor seems to fall off at top end the 750 hp is set at 82 jets at all the corners. the air bleeds are still factery settings.the advace is set at 34 deg.