Longbox55, you said you've advanced to 15 degrees on your distributor. I was having trouble with the same thing several weeks back but with a 390 Holley and a Mallory distributor. I wanted to try but the advice was was not to advance much beyond stock timing (4 BTDC). My dizzy doesn't have vacuum advance just mechanical. It still has a hint a bog off idle...would it hurt to give it a try and how do I know when I go to far? Sorry for jumping this thread a bit.
