Am building a chevy 350 for street use to be put in an 84 camaro (with all acc'y, even a/c).

Was considering one of those smaller (underdrive?) crank pulleys - I know I willl get more HP to the ground, but I was wondering if and what the negative side effects might be?

Anyone run one of these and tell me if the batt stays charged and if the car runs hot?

thanks
chris