I'm going to have a PowerFlow installed in my '77 J model when it goes in for annual later this month. I want to do some before & after testing to actually measure the benefits I see. Power Flow claims it will do these things for a J model: 5 -7 knots faster cruise speeds 10% – 15% increase in rate of climb 0.5 – 1.5 gph reduction in fuel burn at equivalent airspeed Improved Take-Off Performance (100’ – 300’ reduction in ground roll) Increase in Service Ceiling of 2,000’ – 5,000’ Coo