here is what i had to do when i put my 89si cluster in my 89dx. The speedometer was reading like 10 mph faster than i was going, so.... I took off the top of my dash (the cluster cover) and removed the plastic cover from the cluster. Then I got my buddy to drive his 96 civic (i assumed that the speedo was accurate), and he took a walkie talkie with him and when we drove side by side down a free way at like midnight, and when he was at 65, he told me so over the walkie talkie, and i pulled the needle off my guage set and moved it down to the appropriate speed. It took a couple trys and another buddy holding the wheel of my car to do it right. haha, that is the only way i know of to do it, there is probably an easier way out there though...