What I did to slow my car down from 9.0 to 10.0 was make a mech throttle stop(pic) and changed the launch rpm and shift rpm.. was deadly on 10.0 if I could catch the light.. this was on a trans brake
That's the right way to do it. Or you could just fill the bed up with railroad ties. If anybody says anything just tell them you were using your truck to do some landscaping.
In theory, there is no difference between theory and practice. In practice, there is.
If anybody says anything just tell them you were using your truck to do some landscaping. 
