help with fouling plug

center carb is 1-1/2 turns out , timing at 18 deg idles at 850 rpm in gear. vacuum in gear is 11 inches. Its got a 60403 voodoo cam ported 2.02 j heads , crane gold rockers ,
dougs headers , accel stock replacement billet distributor, with orange box. Its just a flattop piston motor about 9 - 1 compression . Nothing special.