I had a way bigger main then you when I ran my 2-1 also. I had 2-1 with 35pwk, PT Mids, 21cc domes, stock airbox - no lid with a k&n filter and I was running a 175 main. That seems wierd, sorry but no help here. If you went from a 162 to a 148 and no help, I would say that's not the right direction. Your filter wasn't clogged or something silly like that before was it?? Is your airbox letting enough air in??