How to stiffen up the rear suspension?

[Stroker-ace]

I want a good firm suspension in the rear of the car, what kind of shock/spring setup would you reccomend? I currently am running 315/35/r17's in the rear on corvette ZR1 rims with 2 1/4" spacers with very little clearance. I am going to get the frame notched this winter but I still have issues with the tired rubbing on the fender's when I hit bumps. I m also getting the fenders rolled at this time, but I would still like to make the rear suspension nice and stiff. Any heklp woudl be appreciated, thanks.


Pic of wheels on rear of car.