autolite 3923's... its what i have and what many of the guys have, basically they last a decent amount of time and work better than platinum or other "high tech" plugs... our engines are old school and don't do well with the newer ****

also changing the plugs is a hugh PITA, so i would definately say: have a long extention for your ratchet or else you won't be able to get to them at all

BTW, i get around 15-17 averaged between city and highway....