Alloy heads

Aluminum are worth the investment. They are significantly lighter. They are more easily repairable. Better castings and give you room to grow. If you race the car, weight is EVERYTHING! Sooner or later your will get to the point that making more power becomes technically or financially prohibitive. What’s left? Shed weight.
A hundred pounds is a tenth! I could be a tenth quicker if I only weighed 130# LOL