help w/ timing and vacuum advance questions
Running a 302, 4spd, new 600cfm Holley mech secondaries, stock Autolite Distributor with points (yeah I know) and single vacuum advance.
The engine was pinging at highway speeds 70 mph, especially going uphill. Put a timing light on her today, and set the timing to 10 btdc, she was at 0 btdc because I didnt have a timing light at the time.
Ok, I checked the timing with the vacuum adavance disconnected and hose plugged. From 10btdc she advanced to about 28 btdc at wot. Then reconnected the vacuum advance and at wide open throttle she is waayyyyy past 40 btdc. I know this is too much. Thats why she was pingning. The question is how do I get her not to advance so much at wot?? I have heard you can shim the vacuum advance, is this true, and how do I do that?
She is also stumbling when I punch the throttle, did it yesterday at the old timing setting, and did it today at the 10btdc, is this because of the vacuum advance, or is that a carb problem? (the carb is brand new). Appreciate your help, thanks,
Dave
Running a 302, 4spd, new 600cfm Holley mech secondaries, stock Autolite Distributor with points (yeah I know) and single vacuum advance.
The engine was pinging at highway speeds 70 mph, especially going uphill. Put a timing light on her today, and set the timing to 10 btdc, she was at 0 btdc because I didnt have a timing light at the time.
Ok, I checked the timing with the vacuum adavance disconnected and hose plugged. From 10btdc she advanced to about 28 btdc at wot. Then reconnected the vacuum advance and at wide open throttle she is waayyyyy past 40 btdc. I know this is too much. Thats why she was pingning. The question is how do I get her not to advance so much at wot?? I have heard you can shim the vacuum advance, is this true, and how do I do that?
She is also stumbling when I punch the throttle, did it yesterday at the old timing setting, and did it today at the 10btdc, is this because of the vacuum advance, or is that a carb problem? (the carb is brand new). Appreciate your help, thanks,
Dave