i used to get 250 miles out of mine.
it was 170bhp with superchip etc etc and i drive like a twat too, lol.
as long as you keep your foot still and dont keep stabbing the throttle (like many people do) then it should do 250 at least.
also its a revvy engine, dont treat it like a turbo where you keep it in the lower rev range, let it buz away and it seems to run more freely, if yu catch my drift!!??
mike