Trick Flows are reasonably priced. Mine are the Standard heads port matched to my intake. My motor will spin to 7k. These guys have 'em for about $1000. You'll need the right length pushrods to avoid valve guide wear.
AFR's all the way, spend the extra money, they are worth the money based on the flow numbers I've seen Box stock, if your spending $1000, whats another $200-300, especially if you are going over 7,000, the more flow the better.