thanks guys nice info , I have been running 107 l/c 255/262 670/650 with 230 indys with 11.4 comp the car runs 10.90@123 mph and good 200 hit 9.57@142 with 1 3/4 pipes full system 105 octane stock block at 3500 lbs 780 moroso hp ,doing a new short with 13.1 cam will be 272/276 700 lift I think I will go 108 ,the gas will be less this time