My stock 350 heads had a wicked crack in them. roughly 80000 miles. No more old junk for me...a large part of the motivation to go with new heads. I wasnt about to go on a treasure hunt for uncracked heads just to find out theres a crack when they get cleaned up.
If I where building a quality engine, I would definitely spend the money for a set of aftermarket heads. Almost any aftermarket head is a better quality head than factory ones because of the increased thickness of the castings.

