Front end setup (Drag Racing)

Actually, you changed the "time" during the launch that the transfer happens by raising the nose. It's probably hitting the tires a bit harder (more sudden) now. Did you check and correct your pinion angle? A pinion that now points up will also change the hit on the tires making it hit harder.

Edit: You can also get a front spring hanger with extra holes to help "tune" the hit. That way you can have the nose at the right hieght, the pinion angle dead on, and the front of the springs down slightly to ease the hit on the tires.