Performer RPM with Different Spacers
This graph show three dyno tests; a one inch open spacer (shaded line), a one-inch four-hole spacer (solid line) and a two-inch tapered spacer (broken line). The Performer RPM wasn't super sensitive to spacers in our application. It did like the two-inch tall tapered spacer the best, but the one-inch tall one was very close. No spacer also worked fairly well so if you don't have the hood clearance to run a spacer, don't worry about it.