You asked about shifting it at 6,000 and valve float.Given it being your D.D.,I suggest you short shift it and develop consistent E.T's.For you to have fun without a dedicated race car,you really don't need to go as fast as the engine will allow.Wining is pretty cool with consistent times.Wifely sees that and thinks "hey how about that...............He won..............and brought home $75.00 bucks..........................ya know maybe we could..........."