Well i'm about to have my worked iron GT40's for sale here in a week or two. I know you said you want aluminums but these heads have been on a flowbench and they outflowed twisted wedge heads but just a little bit so i thought i'd say something. Anyway i'm willing to let them go pretty cheap considering the amount of porting/polishing/milling/springs/valves that they have.
How much are you looking to spend? I'd sell mine if the price was right. I have a GOOD valve train with FTI p/s 3 springs with the spring height set, new seals and they'rem ileld to 55.6cc chambers.