160 mph speedo

If I added a 160 mph speedo in my car will I still be able to use my stock 140 kmph speedo?

because i would want the 160 just for fun to see how fast im going and then the one in kms for keeping it on the speed limit on streets

Do what I do, drive around with the 160mph all the time. You get use to knowing your speeds in KPH pretty quick.

30mph = 50kph
48mph = 60kph or so
70mph = 110kph or so.

Just:

kph = 1.6 * mph

cool

but will my stock 140 km still work cause i dont want it sitting there taking up 4 inch space and not doing anything