Yes only one set of econo heads I had that I got from a friend. I read up on them and they were a part number that were prone to cracking. I quickly hit slightly over 300cfm with the stock 3/8 stem 2.02 valves. I then match ported a Victor W2 intake for them. With a .520 lift Racer Brown cam I ran 9.82 on BP 93 pump gas at 2900 pounds. They cracked 1.5 years later so I sold the two sets of rockers and intake I ported. Great heads but heavy and expensive to build right. I always questioned myself what if I would have had the race head with a 2.08 valve. If I remember right I shifted that combo at 6400 rpm. They have a beautiful short side that reminded me of a set of AFR 220 Chevy heads I did for a friend
