I'm not debating the logic behind AL heads. I've spent past $1200 on 3 or 4 sets of iron heads in the past year. The fact is, these guys either didnt want AL for whaever reason, or decided to cut the $200 difference and run iron factory. RPMs are upt $1300+ now, and the arguably obligatory fix up another $200. Yes, they are lighter, yes the chambers will help with the pump crud now, yes the ports flow better even in OOTB form, yes they look nicer. But, it comes to "I dont have the $200 more. Just redo the iron". As far as HP, I've got several 440s running around with what I'd call amature porting (read as mine... ) that make close to 500hp. It's not hard to do. But to get that on a 383, that's a bit more of a stretch unless you plan to run higher compression and cam/rev them. Then it's not really that hard either. Hence my suggestions.