i have recently modded an old dynamite .12 i have it running pretty good now and it does have more power, but it still doesnt have any low end torque how do i add low end torque i currently am running the stock tune pipe on the firestorm the one that came with the g3.0

There are a few ways to go about it... One way is to give the engine a higher trapped compression ratio. Easiest way to do this is use less head shims.

it doesnt have any head shims could i grind down the head instead?

NO!!! I would get aluminum clutch shoes and stiff clutch spring(s). Might also want to change gearing too.