Tyre size question

[Zlornick]

I bought a 1990 240 wagon a couple months ago to replace my beloved 940. Still have the 940, but it's soon headed to the junkyard, unfortunately, as it was rear ended last fall. I've been over at the 700/900 side of the forum a bit, they are a fabulously helpful bunch.

I've been stripping the 940 for comparable parts to use in the 240, which aren't nearly as many as I expected, however:

The 940 has newish tires 195/65 r15 91h. maybe 4k miles tops on them, still look great.

The 240 has not so newish tires 195/70 r14 91h. Decent amount of tread left, but obviously more wear than the 940s... also, they seem to be of lesser quality.

Any reason I can't flip the two sets? Would that extra inch of radius be problematic? I've seen some stuff about performance differences, but haven't found anything conclusive.