when i set my timing by total timing I have low vacuum about 11-12in at 800 rpm the cam I have was a cust grind from comp. to give 15 in of vacuum to pass my class rules the only way i am able to get enough vacuum is to over advance the timing and with the new dist it still doesn't pull 15 in of vac. but when i switch back to my old dist it will pull 14.5-15 in of vac. with about 18- 20 deg. base timing but that makes total timing 48 -50 which i believe is to much i tried the small spring removed and it did help bring timing in by about 3000 rpm but still can't get vac. thanks for any help