Not to jump the gun here, but Jim was responding to advancing the timing but Joe was asking about advancing the cam.

Most street motors respond well to about 4 degrees advance for the cam (measured at the crank, of course). It boosts the low end torque a little without killing the top end. An adjustable timing set is really the only reliable way to go.

I use a gear drive wich makes it easy to vary the timing over a pretty wide range. However, it still takes all day to strip the front of the engine and move the timing, then degree the cam to be sure you went the right way.