Vintage wheel chart 65-66 mustard
"Backspace or "Offset" is the amount of wheel that goes inward. Its measured from the flat surface (Inside of wheel) to the inside edge of rim. If you lay a wheel down with the inside up, set a ruler or srtaight edge across the wheel and measure fron the center down to the backside of the center hub area= backspace.
Id try somethng like a 15X6 with a 215/60 with 4 inch backspace. That way you can also rotate your tires.