^ It might dull the timing when you're bumping into the unloaded limiter. Try flooring it and dropping the clutch right before you actually bump the 4200 limiter.

But in all honesty, I don't think this car really has the torque to spin both huge rear tires out of the hole... yet. Probably do better slipping the clutch in from 4000 rpm. Just be ready to replace the clutch if you do it often.