Iron heads? I can answer that in two words. Windsor SENIOR!
I had a set on my last motor, and they ROCKED!!!! Had them redone, and sold 'em on ebay for $700!!! Like a sore peter, can't beat it!
Iron heads can be ported, and flow just as much as aluminum, some guys say more, but the only drawback is the weight.
Only problem when hunting down a set of Windsor Sr. heads.... The rights to the casting changed hands several times. Went from "Dart" Windosr Sr., to "World Products", and now I think the current owner is Roush, then I lost track of them.
Latest Summit catalog has them listed as Windsor R 200 (R= Roush 200=intake CC) Part # WRL-053040 or WRL-053030 and some suffixes depending on what you want.
If I HAD to run iron heads, these would be the ones. I had a set, they ROCKED, and I loved 'em!!!
EFI intakes? I'm gonna gracefully bow out of that one, cuz I plain flat out don't know shizzle about EFI. Throw a carb on it, and we'll talk. hehehehe