Tires in my avatar pic are for cosmetic purposes only. (P345/55R15) I blow them off at will on the street if I jump on it. At the track I use 29 12.50 X 15 Hooser slicks. Tires spin about 5 feet at launch.
As stated, I've tried the 3.09 gear set. It didn't work for me. My short times were the same as the 2.66 set. My ET's were also about the same. I twisted 2 3.09 input shafts and actually wiped out the cluster gear with the last twist...
My car being heavy, I thought the 3.09 set would work real well. In my case it didn't, so I'm sticking with the 2.66 low gear set.