273 Overheating problem

I've been having some heating problems and noticed my front pulley (attached to water pump) is smaller than other cars. I think it's from an A/C car. I'd say it's about 1 inch smaller in diameter than the others I've seen.

I'm guessing this makes the water pump rotate faster, thereby making the coolant flow faster and not cool the motor as well, right?

How much difference would a larger pulley make?

I also have a pinhole leak in my radiator, does this affect the pressure and temperature?