I guess tire size are same in numbers but differ in physical size, depending on which part of the world you are in. I have seen George's bricks, and they looked perfectly fine with 195s on stock rims. On my 74 144, I still run the original 165/80/15 Kumho Powerstars which my dad imported from Korea shortly before he passed on. We tried to mount Dunlops, 195/75/15, but the sidewall looked pinched at the rim, sloping outward and it looked weird. I have a set of Virgos, and are waiting until the Kumhos wear out. A friend of mine has a set of Virgos with Yokohamas 195/75/15s on his 71 144s, and has no clearance issues. It drives better too round the curves.

As for the high revs at 60 mph...my M41 still resides in my garage, waiting to be mounted...