Hey there,
I don't really have any specific recomendations, But I have heard the same thing. Alumenum and Iron heads are not all that different except in weight. Its all in whats done to them. If you are interested I have a set of cast iron heads that are bare. They are origenal 487 chevy heads. I have read on the internet that these heads have lots of potential. they are bead blasted and fluxed. If you want more info, ill post it.
good luck in your search
later - zach