I think the Chevy manual says something like 4-6 degrees initial at the crank. Denny will have straight scoop on this, but most everybody uses more initial, like somewhere between 10 and 14. When we had good gas we could run 36 degrees initial and centrifugal combined, but I might pull that back a little these days to 33-34 with good pump gas. You'll get varied opinions on the rpm point where all the advance should be in, from 2,400 to 3,200.