[Tom Goldman]

At that weight 20-23# is a good starting point.
you really need to run a test session , increasing the pressure each pass to see where the tipping point is for spin and then back down to find the highest pressure that yields the quickest 60'.
Shock settings will have a big effect on your final pressure also .
Bias tires are so forgiving you can miss by a half pound and get away with it , Radials ,they love to teach you their limits, usually at the worst time !.
Before you start ,invest in a good quality gauge that does not greatly exceed the pressure range you expect to run and use it only for the slicks.
A zero to 40 # gauge with 1/4 pound increments is usually the ticket ,especially since most dial type gauges are most accurate at mid scale.