I went to the ANRA event this weekend and had a blast! Just put new tires on the car: M/T Pro Drag Radial, 9x30-15. These replaced 10.5x30-15 bias ply slicks. For my first run, I used 16 psi. The tires gave me a 1.65 60'. That was terrible compared to my old tires that gave me a 1.58 typically. Everyone told me to go up in pressure to make them work better, but I instead went down to 12 psi, which was the low end of the recommendation from M/T: http://www.mickeythompsontires.com/tech-bulletins/street-air-pressure-guidelines

At 12 psi, the car gave me a 1.52 60', which is the best ever with the car. Multiple people said I should go up on pressure rather than down and that if I put 20 psi in the tire, it would do even better. Since I was going into competition rounds, I didn't want to change anything and ignored them. I continued to get great 60' times.

The next time I can get some T&T runs, I'm going to try higher pressures to see what happens, but I'm very interested in the experience of you guys. Relevant specs on the car:

About 3300 lbs. with me in it
Super Stock leaf springs + Caltracs and drag shocks
727 with 3500 stall, 4:10 gears
500" big-block with a 260 @ 0.050 solid roller