I recently installed a full dash cluster in my '87 Sportruck. The cluster I obtained came out of a '88 XJ with a 4.0, so the tach is off (by 33%, I think). Now, I know that the proper way to adjust a tach is to install a reference tach, start the engine, and adjust the on board tach to match the reference. What I was wondering is this: since Jeep only used a 4 and a 6 cyl engine in these vehicles, would turning the adjustment knob all the way over to the opposite end of the adjustment range get me the correct readings, or should I just do it the proper way?
Thanks in advance!