The condition any heads are in weigh in here. I picked up a pair of angle plug 492 heads last year that ended up being so rough, by the time I stripped them down, I tossed everything but the castings. They needed new exhaust seats, guides, valves, springs, retainers, locks, etc... They were going to cost me about $750 to just get back to useable shape. :sad: I sold them for $80 on Craigslist, just so I wouldn't eventually waste the money on them only to be outperformed by a pair of junkyard Vortecs.
My point here is, if money IS a factor, go with the most complete, best condition head you can come up with now. Buy something that the seller took off for a set of aluminum heads, and has bagged and stored them properly. Proper storage indicates "ready to use at a moment's notice". Tossed in the corner by the workbench does not.