i am having the bigger springs for mine the only thing you need to do to run the better springs is the seat were the spring goes has to be opened up a bit ,,Bone and Taliban Dan are sending my heads to the guy who ported his and i am going with the same setup bone has ,,they are also doing a 3 angle grind on my valve seats ,,i am calling comp cams on tuesday or wednesday ,,i emailed them and they sent me a response back saying that since i am going with the different springs i could go with either one and im leaning hard on the 270 ,,,if i dont have to switch valves and rockers i will most likely go with the 270 ,,,