If you go into it knowing you will need to buy a $35 60 degree countersink (for steel), it is no big deal to make the wheels right.  But, you do HAVE TO MAKE THEM RIGHT or they won't bolt on correctly. Other than the lug nut holes, the wheels seem to be just fine.  I mounted the two new ones on the front and they balanced out fine and run true.

One consideration for use on a 65-66 is these wheels actually have a measured 4-3/8" backspacing, not the 4-1/4" as advertised.  That will allow them to fit just that much better with less chance of rubbing.

I saw a 69 Boss 302 at a show last weekend that had American Racing alloy 15x7 Magnums on it.  They had a very high polish and had original style center caps and looked quite at home on the car.

Remember the wheel I put in my press to make it unusable?  CJPony told me to keep the two wheels.  I straightened that one out with a hammer and it is going in the trunk as a spare tire.  I even bought a new 235x60R15 tire that matches the other four tires.  I got the wheel so straight you cannot tell it was messed with, and the main damage was done on the back side, even though straightening it back out made it totally usable.

I had 15x7 Magnums on my 66 many years ago with 225x60R15 tires. Fit good but had to roll fender lip in front