When your running one to one linkage the interconnecting linkages need to be at the same distance from the throttle shafts, not one higher than the other I've used the Eddy carbs and linkage like your suing and if you want one to one lower the linkage mounting hole on the back carb. to macth the front carb. If you want it to be progressive linkage then the back one needs to be higher than the front so the back carb.(primary carb.) can open some before the front carb. starts to open