I know this question is like the old ' How long is a piece of string' but I have a fresh mild 308 running a Holley 600 vac secondary,Crane 286 cam, Procomp elect. dizzy,Edlebrock manifold to Pacemaker extractors.I'm currently running 8 degrees advance and the carb is fitted with 64 mains and the second lightest vacuum spring(yellow) and a 6.5 power valve. The thing runs pretty well but has any one got any better settings to suggest.The mixture screws only like about 1/2 to 3/4 turns out which seems strange and the plugs are white/tan on the porcelin but black on the outer edge.