who to buy rhs heads from

The only advantage in Aluminum heads is weight and repairable, if you had a eddy head in aluminum and one in cast iron they would both flow the same but the cast iron one would make slightly more power due to holding the heat in the combustion chamber better, thats why you always want to increase the CR when changing from iron to aluminum, aluminum sucks the heat out of the combustion process much quicker, so if your only around 9 to 1 and are not wanting to change pistons i would look for a good iron head, if your open to CR change go aluminum but Eddys wouldn't be my first choice.