Clutching will do little for if not hurt top end on ANY sled. Top speed is a result of 3 factors. Horsepower, RPM and Gear Ratio. Clutching, will however get you there faster and increase the fun factor. If you are looking for more top end, I would suggest having Allen machine your helix and split collars (in primary). I ran a 123 on GPS with all stock clutching with exception of machine work on primary and secondary, changing gearing to 40/24, and running an Attak secondary spring (white) set to 60 degrees. Bone stockers out of the box run 115-117 on the gun. Whats interesting is you would thing by gearing down you would loose top end, but in this case I gained. Stock gear ratio is 1.58, and changing to 40/24 it is 1.66. I think a 1.58 ratio is VERY hard to pull with 150HP. Gear it either 40/24 or 38/23 and see what happens to your top end.