I have a Mega Monster 200-4r from Monster Motorsports and when I manually downshift at speed it doesn't decelerate the engine like I want it to. It just sort of free wheels. I am running a TCI Street Fighter 2200-2400 stall convertor. Also it doesn't shift WOT when I would like it to. I want it to shift at 6000rpm and it verys between 4000-5000rpm.

The shift points are controlled by the govenor. You make be able to hold the gears down in first a little longer but it will still overide and up shift. You can hold first as long as you like. As for the overun braking there will be some in the d3 and d2 positions and once the gov allows there will be alot in the manual low position but if you downshift to manual low the shift will not occur till near 40 moh or less .