I do not remember the formula

5hp is pretty big on single phase. Does it dim the lights in your shop when it starts up?

Not at all. I see no voltage drop in the line while starting or running.
As to the pulley's, I did not get into it that far. Guess I do not know enough about it to play with them.
I took a 4" x7/8 pulley (that looked about right) for the motor and used the pulley that came on the compressor pump

The best part is, I am pretty sure, I spent less than $400 to build this.