How much will adding 16 lb to my car affect ET/mph(rotating weight)

I have been wanting to experiment with chassis mods with my SS Spring...... More accurately Torsion bar tuning.

When i do my burn out the rear kicks out to the right, when i loose traction down the track it wants to go right also.
with these skinny cheater slicks, it was painfully more of a problem.
So after i had done all i could to make it go down the track with my right foot..........I got my big long 1/2 inch beaker bar out and 3/4 socket. Slide under my car and loosen the torsion bar 1 full turn. (right side only)
Burn out and launch seem to be just a little less of a sideways spin. So i turned it one more full turn looser. I know for sure, now, i'm going in the right direction!!!!!
After a couple more passes i climb back under and give it one more full turn looser. Burn out is straight and the launch is under control, enough, that i can even note who and what car was in the other lane.

So now its time to do a full throttle, out of the hole, and see what happens........It spun hard, as i suspected it would do.
It spun all the way through 1st gear and half way through 2nt............. The surprise was that i didn't have to lift!!!!!!!

I still had to steer it, but the fact that i could control it, and NOT lift, was AWESOME!!! I wanted to make a 2nd run and verify what i had felt and done on the last pass.................But good old Mother Nature said that's enough!!! Thunder Cloud Ended the day.