Volvo Repair: odometer & timing belt replacement, timing belt replacement, cam engine

Question
How big of a job is it to replace the odometer on a 91' 240? Replacing the timing belt this weekend on my son's 240. Have not done this on a volvo/overhead cam engine before. Looks pretty easy as I am very mechanical myself. Been turnig wrenches for myself and others since I was 14. I'm 50 yrs. Have done everything from complete motors to complete suspension replacement/overhaul.

Answer
it is pretty easy to replace the odometer just mark the wires so the proper ones go back on in the proper places.there will be one wire not used  if there is no tachometer and if you install it by accident it fries the speedometer.remove 2 square trim pieces by radio then the headlight switch knob and dimmer knob them the trim plate behind it.then remove the 4 torx 25 screws.

Rege