Lack of full movement at one extreme usually means that your bell crank has reached the limit of it's own travel before the carburetor arm has. If this happens, it means that the carburetor throttle arm travel is more than that of the bell crank and the bell crank throttle arm throw needs to be increased by selecting or drilling a hole further out on the bell crank arm. The idea is to have arm movement that is at least equal to or a bit longer than the carburetor throttle plate. "carburetor full open to full closed" This will ensure that the full range of throttle settings can alwasys be achieved. Smooth movement without binding is the goal. The bell crank length of the arms must equal the travel of the carburetor throttle arms. The optimal arm optimal position is 90 degree. In selecting the arm length the required throw is the primary factor. When you have a choice use the longest arm length you can. The forces on the bearings and links are therefore minimized. By using long arms you also minimize the stress on the bearings, if any. Brass bushings against a steel pivot shaft is ideal. Jeg's Catalogue adjustable bell crank will bolt up to the Chevy 235ci engine and solve many linkage problems using the offy and fenton set-ups.
