hey guys i recently put a fairmont ghia speedo in my ef gli its got a ef xr6 manual in it and 345 diff ratio the standard speedo used to show 100 kmh when the revs where at 2000 rpm in 5th now with the new speedo at 2000rpm the speedo says im doing 90kmh does anyone no how i can fix this or re calibrate it? cheers

I bet you bumped one of the needles when swapping, just move it back/forward to the correct position.