Third member swap between cars.

You never mentioned the gear ratios but depending how different they are you may want to change the speedometer pinion gear in the trans to get a truer reading on the dash. The difference is usually not much but a GPS or the one on your phone can help you determine how much it is out and decide whether the difference is worth the trouble. I always check it so at least I know if it is up or down from what it should be.

There's a couple of charts in one of the stickies for this forum that should help if you decide you need to change the speedometer pinion gear: Speedometer Gear Charts - Clarification/Differences