the heads on my 72 413 are 2899943 heads. i want to put put bigger valves in it so i can get more air. i found 413 flat tops for it. i am ordering a .578 cam and a edelbrock performer intake. will i need bigger valves or can i get the same ones. i heard these heads dont have hardened seats in it either. is it true? Need help figuring these heads out. thanks guys.
