>>Have you measures the width of the rims, i.e. are they 5.5" or 6" rims?
Vega GT wheels are 13x6" measured between the mounting flanges.
I mounted one, without tire, on the back of a square-arch parts car and
found maybe 1/2" of clearance between the inner edge of the fender lip and
the outermost edge of the wheel flange at top center. This would severely
restrict your choice of tire sizes. You could probably gain ~1/4" by folding
the fender lip flat.
I've used a set on a -round- arch car with 185/60 tires with no problems.
Ed in NC