www.powerheads.com is a very good source for ford iron heads that have been ported, polished, and a valve job. You can send them your heads and have everything done or they usally have heads already done up and can send you a pair. you still have to send your as a core but you don't have to wait for the work to be done.
Best advice I can give is make sure the rods are in good shape. Take them to a very well know shop to get them checked out. The rod bearings have spun twice on me in my 428. I finally got smart and paid the money for a "real" race engine builder to put my short block together. He said that the shape my old stuff was in he wouldn't even put the motor together until I got a new block, crank and a couple of new rods. Now my 428 still pulls at 6,200 rpms on the street. Haven't gone past that yet but will when i get it to the track. My point is you get what you pay for. Pay the big bucks now and you will only have to do it once instead of 3 times like I have.