are ther any other changes when installing the 120 speedo in 1980 zx?

 

I think you will find it is a 130 mph speedo if it is out of a 1979. Nothing special to do. Just pull the cluster unit out following the FSM. Sometimes it is a bitch since it wants to hang up on the dash. I had do mine several times so I got pretty good at it.

The 1979 only had a 5 digit odometer. I wanted to retain the 6 digit in my 1980, so I sent both the 1979 and the 1980 off to Ft. Laudedale speedo shop and them blended together. Also had them rebuild and relube as well as set the mileage correctly.

Install was a piece of cake if you install the short piece of speedo cable on the cluster unit before putting in car -- I didn't. Had to remove it and do it right. Then I left lint on the inside of cluster unit. I took it out one more time to clean the plexiglass on the cluster unit. I finally got it right and took the car out and ran it up to 90 mph and checked it with a GPS unit to be sure it was calibrated -- spot on.

LOL