Hy jon6.0 and guys, those are three piece "Kelsey" style wheels peculiar to Chevrolet, five studs for front mount, while the rear uses the full ten studs, there is actually a plate which goes on over the front wheels/studs before you put the nuts on, this plate covers the five unused holes. As for radials, yes you could use them, if you can find any made in the size you need, hope that helps.
