worked stock heads vs aftermarket heads

[V8SHME8]

keep in mind that cast iron heads make more hp that aluminum heads but the advantage is that aluminum heads keep the car cooler and they are lighter weight which means more mph on your car.

Aluminum 0.902 joules/gram degree C
Iron 0.450 joules/gram degree C

q = Mass x Specific Heat x (Tfinal - Tinitial)

You might want to check your physics out there buddy.