Performer RPM modification

Indy heads are designed for high performance use so they don't expect that you'll be using an intake with exhaust heat. Most people want to get rid of the exhaust heat under the carb since they want the intake as cold as possible for max power.

If you have a weird combination where you want high performance heads plus exhaust heat you'll just have to fabricate a solution. I've seen guys modify the valley plate with a little cup in it but that seems like a lot of work.