I installed Mustang's Plus 4 1/2 standard eye rear leaf springs on my 70 Mach with Koni shocks. The car sits way too high in the rear and is as stiff as a board. The shocks are almost fully extended and your push on the rear end and there is no bounce. I mean the car does not budge. I understand you need firm springs for performance, but I am afraid I wll bounce all over the road. I have the Koni's set to medium. I am thinking about going to a mid or reverse eye 4 leaf. All parts are installed on the car except for the rear glass and I don't think that will make a difference. The leafs I have now are rated at 175 lbs. The stock rating was 138 lbs. The 4 leaf springs are rated at 175 lbs. I am not sure if they will help. Anyone using what I have described? How does it run on the road? Any recommendations?