You aren't going to get a 15x8 under the front of an unmodified 65/66 car. You CANNOT run 4.75"(or 4.5") BS on a 15x8 in the front - it will be solid into the upper balljoint.
A 16x8" rim w/4.5 BS
sometimes fits in front with minor mods, but it's REAL tight, and can vary from car-to-car. Once again, the upper balljoint/control arm is an issue.
The reason the 17" guys can run an 8" wide rim is that the wheel is tall enough to clear the upper balljoint, permitting you to run the extra backspace required (4.75").
Dodge needs to read that wheel chart!
How many entries are 15x8 in front??? Only 1 that I saw, with TONS of 7" - there's probably a good reason for that...
And, do you REALLY believe that ONE guy made the wheel fit, when nobody else has??? Or maybe that guy likes to exagerate (or doesn't know the correct way to measure a wheel?)