adjust advance curve

Can someone provide a technical read on what direction I may need to adjust my breakerless Mallory HEI dizzy? First my engine: Cam is .487 intake .508 exhaust, duration 234*/244* @0.50 110* lobe separation 383ci, vortec 2.02/1.60 heads, 750 cfm Motor's suggested initial timing: 12*. Will not...