You might compare the two dists if the rotor to bottom shaft tang are "clocked" the same in relation to each other on both of em, that could throw phasing off. this would require pulling the new dist to check it. EDIT you can line up a tooth with the magnet in both of em & see if the rotor clocking is the same & I'm thinking you could eyeball/compare the pickup wiring (path/colors) to see if they are both identical