Correcting Speedo after Wheel change.

Yes, rear ratio and actual tire diameter.
But sometime in the mid-60's, they changed the speedo pinion. So you need to find out if your trans takes the common "long stem" speedo gear from the mid '60's through the '80's somewhere, or the earlier type. When they went to more electronics, they stated using a short stem speedo gear. (I'm not familiar with the early speedo gears. At work and don't have time to search for more details.)