The rallys you have now are probably not going to work with the lowering you have in mind. They're too wide and the backspacing is not near deep enough.
Chevs of the '40s has some wheels that you can custom order for backspacing. On a 5" wheel you'd probably want "0" offset (2 1/2" backspacing), but man......they're expensive.
You could use most any stock 15" X 5 or 6" 6-lug truck wheel. From '55 to '60 they have 3 clips for stock hubcaps, '60 and up went to the "nubs" to hold the hubcaps on (these are the ones I'm using).
