Mike, Yes! Floor shape is critical to low lift vs high lift flow. Part of the reason you may not have found a good compromise is because it all depends on the cam profile, most specificly the rate of valve opening and closing. The slower the rate, the more low and mid lift is important. There is also a sound relationship between throat size and valve head OD, which can be influenced slightly by seat and tulip angle. George, Nope, name is Aaron. We use a combination of flowbench, CFD and running engine for development. For rod ratios we did some testing running from 1.5 to 2. Friction was the biggest thing influenced, with VolEff and burn rates being within the normal scatter. Honestly the baro and humidity would influence the burn more than rod ratio. Friction seemed to be the lowest around the 1.75-1.8 mark. The best tool I have ever found for power development is pressure xducers for in cylinder crank angle resolved measurement. Unfortunately not in the realm for most of us.