Radiator install question?

Don't worry about the 1/4" as long as the radiator is not touching except at the mounting flange. You don't want it touching anywhere else because the possibility exists that a hole will eventually get rubbed in the softer metal of the radiator by the car body. And watch out for any bolts mounting braces and such. I almost got caught by the bolt holding the brace going back to the k frame on my Barracuda. Didn't realize that the radiator support was curled up a little bit on the inside edge and I had no clearance.