Originally Posted by Maximo

Is your engine Clocked ?

the 97T is a very hot plug for that engine IMHO.......stock or modified.......A cooler plug will definitely help mileage, but I wouldn't expect the greatest run time from a stock F11 as it runs very high blowdown timing......... Also the F11 is a very tight engine, I wouldn't expect it to wake up till its about 2 gallons old...