If i advance my timing, will I get bad fuel economy?
Ignition timing and fuel economy ARE directly related. In fact, fuel economy is one of the main reasons distributors have a vacuum advance. Advancing the initial timing up to the point that the engine knocks under heavy load and than backing off a degree or two is a good way to set it for both power and economy. Compression ratio, temperature and the octane of the fuel you're using will also play a major part in how far you can advance your timing without knocking. I have my '85 Mustang GT set at 14 deg BTDC and notice a definite improvement in throttle response. However, in order to prevent knocking, I have to run premium gas (running that far advanced doesn't help my pocket book due to the $$/gal price, but it definitely is more fun to drive). The stock initial timing on a '68 302-2V is 6 deg BTDC. Try advancing it to 10 deg BTDC and see if you have any knocking with the fuel you're using. Knocking can destroy your pistons over time if you're not careful. Good info below:Fuel economy and timing are not really directly related ...