What year car? Points or electronic ignition? Where is timing set currently? Is there a vacuum advance? What gasoline are you using? If spraying at the base, are you sucking fluid through the throttle shafts which will give you a false reading?
74 with a 72 340. electronic ignition, will throw a timing light on it tonight and get back to you on that but ive gone up and down. Sound gets worse when i advance it. there is a vacuume advance and it is operating. 91 octane fuel.
