I looks like the motor mount is offset from the plane of the plywood backboard by just the width of a 2x4 (1.5-inches). I think you may run into problems (i.e., chain skips) because, ideally, you would install the linkage kit near the center of gravity of the sled… and this will be much higher (further away from the backboard) than 1.5-inches. You may consider pushing the mount out (I don’t have the exact distance off the top of my head) so that the motor’s sprocket will be at the same distance outward as the chain’s connection point with the sled. Keeping it all in the same plane will reduce the chance for chain skips.
Read this post (expand it down clicking that little upside-down caret in top right corner… the formatting is better):