The front of the mount happend to be right at center of the old mount. Using large vise grips i did both sides at same time. This way i could set them both perfectly to where i wanted them. Do not use the rear end of the frame for reference measurements. I learned on my 4runner and same for this that the ends of the frame rails are not perfectly square with each other. Instead i used the old feont leaf spring mount and bed body mount on the frame as a secondary to be sure.