Hey i found out that im making 15 mpg, before when i had stock everything i was makeing 16, I know its probably not to big of a difference but i figure the exhaust and the under drives would help a lil. any ideas? what do you all make to the gallon? I dunno if this has anything to do with it but i do put in a quart of oil and some radiator fluid like one of the previous posts every 3000 miles. im getting some 373s tomorow but im having second thoughts hope fully i wont be makeing 15 gallons to the mile