Hey Jack, I obtained indexing washers at a local speed shop. Accel puts out a 30 ct. 'variety pack' w/ 10 of each size washers. Don't expect a noticible increase. Not to say that it doesn't help, but I think mpg gains are on a case to case basis. I have some extras if you want to PM your name/address I can send you some (may have to double up on some plug/slim pickings-mainly thin ones left). But at least you wouldn't have to drop the $ before checking out any possible results. Good Luck.