Jeff, how the heck did you get 50/50 weight distribution on a 70 road runner??? :shock:
Give us more info, hp, what time/mph you looking to run, gears, etc.
For 50/50 is the motor moved back a lot??
The thory of ladderbars is to try to pick up the front of the car transfering weight to the rear then moving forward.
My first guess it that you are trying to pick the car up too far forward of the c of g , hitting the tires too hard. The front of the bar may need to be raised.
Also what springs in the back, shock settings, it all enters into the equasion