speedo problem
 

89 mustang lx, 5.8L, 4.10s, manual 5spd. When I bought the car, it had 2.73s & the speedo was fine, this is in Canada, so it goes up to 200km/h. After I changed to 4.10s, I haven't been able to fix the problem. If I'm going 60km/h, it reads 100km/h. I already tried the 23 tooth speedo gear but it didn't help. My tire diameter hasn't changed since, so I don't know what else to do. The only thing that's different is the cluster, it's out of a 4cyl mustang. Could this be the problem? thanks

Re: speedo problem
 

It didn't help the problem at all or it changed the speedo readings but but they are still not correct?