Will 235 70 15 tires on a 15x7 rim with 4.25" backspace fit on a 1965 Galaxie on all 4 corners?
I suspect it would, but unless someone's got that exact stuff on their front end and can tell you for sure...
On my front end I run 15x7s with a 3.75" backspace and although I'm running a 215 tyre there would easily be room for a 235 on there - with an extra half inch inside the wheelwell with your backspace... not sure, sorry. On the back my rears are 15x8 with a 4.5" backspace and 245s. 255s would fit, just, but 265s would be pushing it.
If you have the wheels to hand (without tyres on them), I'm sure if you mounted them and get your tape measure out; you'd be able to tell if you were going to hit anything on full lock. Give it at least 1.5" either side at approximate sidewall height for a 235 size tyre.
EDIT - the rear end won't be a problem, but the front end is where you might run into trouble.