Slide-A-Links???

I have them in my 73 Dart Sport 340 4 speed(450hp)They make my car hook really good.Sometimes I think I have 2 much traction.The good is they are adjustable which I think I need to adjust.I ran 12.88 at 108mph 2 months ago.Have,nt been able to get lower.I should be at like 12.1 or 12.2 at that speed.I,ve got to adjust and see what happens.Runs 12.8-13.0 all day.