Hello again everybody, anyone know a lot about porting. I want to increase my gt40p heads combustion chamber from 58 to 74-80cc if possible. I notice that the combustion chamber isn't a full circle and leans more toward the exhaust side of the head. Can I widen out the chamber towards the intake side of the head and increase the combustion chamber volume? If so is there anyway to tell how much material I should remove. I need to lower the compression for my 81mm ball bearing turbo. I'll have a 4340 3.75"stroke crank, 6.2" rods, and kb step dished pistons from summit. Could I lower the compression by using a shorter rod? I figure I can go as low as 7:5:1 with my turbo. Any help would be greatly appreciated