What is the max boost you can push through their standard blower?

With a 4" pulley, and stock exhaust, you should see about 7-8 psi with a PS1. With headers and a good exhaust system, maybe 2 psi less. But, all systems vary somewhat.

Smallest pulley you can run with a P1SC with a stock 8" crank pulley is 3.49" for a 6600 RPM redline. Otherwise you over rev the blower's max speed of 62,000 RPM. Higher redline requires a larger blower pulley.

P1SC is capable of 30 PSI but on an LS series V8 it will be significantly less. 1200 CFM is the flow rating of the blower as well.