You will have to get the corvette brakes on the AFX spindle and measure. You're going to end up with more front spacing than you think you'll need because of how the corvette brakes work on the AFX spindle.
Unlike stock spindle stuff, the hub flange is inset, specifically with this combination. The corvette rotors don't move the rotor face back from the hub flange, so you do also have to contend with the caliper where typically you don't. The typical cast wheels that are popular from brands like American Racing may struggle with caliper clearance as a result.
A 255 tire is best suited to an 8.5" wheel. I would think that width would be fine in a 67 LeMans, but you'll have to get it situated where it needs to be with the brakes you're going with. Buy those and get them installed, then brake out the straight edge and rulers.
The rears are going to be a little bit better to contend with, but you'll still have to work around the caliper. If you go to Tobin's site at
www.kore3.com he has templates that give measurements, or that you can cut out and check with wheel manufacturers on spacing.
I can tell you definitively that the Torq Thrust II wheel does not fit around C5/C6 brakes. I've measured mine as I was originally going to do C6 brakes as well, but it's a no go.