I don't want to re-invent the wheel

Those 325s fit in my 68 as well, with some judicious reshaping of the inners, in strategic spots, with the bfh...... but I had to slow down for the turns,lol.

A 325 on a 10 has only a very small section width more than a 295 on a 10.
This is because they are measured on a checking rim of 70% of the branded size.
So a 295 is checked on an 8" rim. When you put it on a 10, the section width grows by about .6x 2(25.4)"=30mm or to about 325.
And a 325 is measured on a 9" rim. Put it on a 10 and it grows by about .6x1(25.4)=15.2mm, or to 340. This makes them only 15mm apart or about .6 inch difference in section width, and only half of that to the inside where it counts.

The problem is; I have to run my 295s at 24psi to get even treadwear out of them. And the 325s at 20/22. When cornering at 20/22 the tire rolls over onto the sidewall and puts the Comp T/As into the inner fenderwell. The 295s do not roll as far with 24psi, and they never rub. The 325Comp.T/As have pretty soft sidewalls and are easily damaged.So I save them for shows.
Cornering at these low pressures can be a little disconcerting at first.The rear rolls over and steers the car a bit more than I expected; it took a bit of getting used to. It doesn't do it if the tires are spinning, so most of the time............