I had the opportunity to watch an engine builder here in Colorado Springs flow a set of 049 heads. The heads have 2.19s and 1.88s and were ported by Mark Jones aka vortec pro. I heve never seen this so this is pretty neat stuff to me. His mid lift numbers were great. 294 cfm @ .400, 330 @ .650 on a super flow bench at 28" He can get a set of 049s to flow over 350cfm. I know just about everyone on here runs aluminum but its pretty cool to see a 700 horse iron bbc with 049 heads.