i have bought a 91 z and i would like to know if iam going to have any trouble changing the speedo clocks over from km to mph

I have a 93 import. I changed the clocks over to UK mph. I had to remove the sppedo from the UK clock set, and put it in to the Jap set. All worked very well, and the speedo is 1mph slow acording to the SVA rolling road. I did not want to mess with stickers etc. UK clocks hard to find though, and I paid £120.00 for mine. people said it was too dear but try and find some.