Well....I don't know what kind of symptoms your blown head gaskets were giving you but you might have to look at the block as the problem. Cracks or warpage or both.

Also I would have the cylinder heads pressure tested. I would also check and make sure the head bolts are not bottoming out on a short threaded hole or that they aren't bottoming out on some trash in the bolt holes.
Dale

 

If you are blowing head gaskets after WOT runs then you need to make sure you dont have a problem with your fuel system (lack of).