I thought I would post some results on changing out the stock 496 heads and exhaust to the Raylar/Dana combo. I didnt change the cam or intake for lack of time before summer. No other changes were made to the motor, lower unit, ECM, or prop. I did have to change the fuel pressure regulator to give it more fuel pressure. The boat gained 6.5 mph on top and a ton of midrange pull for cruising speed. I am very impressed and plan to pull the motor this winter and give it the full Raylar 600 treatment along with forged internals and a few other things.