We needed a vacuum source to operate the power brakes and PCV valve. Neither the Race Demon nor the M1 intake had a provision for vacuum. RBRE drilled and tapped a vacuum port in the M1. The 493 has 11 inches of vacuum at its 1,200-rpm idle, just enough for our power brakes. We used the original valve covers as a reminder of our factory stock-appearing days-instead of using a racy-looking crankcase evacuation system, which could have given even more power.