What the heck is wrong with the 289 heads? Throw some 351W valves at them and they work great. Chevy valves work great too but require some unshrouding in the chamber. Compression bump, decent flow and pretty inexpensive.
The early style 289 heads aren't bad but they are getting harder to find and they don't flow as well as the E7TE heads. As far as bigger valves go, since the chamber is smaller you have to do a lot more grinding around the valves. Again all of this is based on a low buck rebuild. If you're going to spend any kind of real money on an engine then aluminum heads are superior to cast in many ways. Of course I'm a cheapo and play musical chairs with the various Ford heads we have laying around in the garage.
Hmmm... i see. I guess I'll just have to breakdown and find a set of E7TEs just to get them along side all my earlier stuff to compare 1 on 1. I'm like you, I run what I have lying around or what I can scrounge up. Every now and again, I'll pony up some skin for certain parts or for certain applications. Jim, the guy who does my machining only charges $100-150 extra (with a valve job) to port any 289 heads I bring him. For larger valves, I just buy the larger valves and the seatwork cost is the same as if a regualr valve job is done and any un-shoruding is done with the portwork. I think I haveon the average $500 into a set of these re-worked 289 heads and they really flow pretty good. I have some flow numbers if anyone is interested. Unaffortunately any head not having 3/8" studs, there is more costs involved because you'd really want to loose the 5/16" studs that most 69-up SBF heads had.