The 196 6cyl in my '65 Rambler is mechanically sound and other than a goofed up carb, it ran fine also.. I have a '65 Rambler American TSM and in the tune up procedure it has a listing for premium fuel and regular fuel for the timing adjustments.. when running regular it says 8* BTDC and running premium, it says 14* BTDC.. If I switched over to running premium, would there be any noticeable difference if I advanced the timing to 14* BTDC?