4th Gen wheels can be used by adding adapters about 1.5" - 2.0" thick.
We have a "Wheels and Tires Forum", with a "sticky" thread covering a 3rd Gen with C6 wheels. That particular car used a wider 4th Gen rear axle assembly, but it could have been done with the 3rd Gen rear, using the same 1.7" adapters he used in the front.
Wheels and Tires - CamaroZ28.Com Message Board
Since you already have a thread on "Wheels and Tires", we'll close this one.
94 Formula A3+1: 381ci all-forged stroker - Callies Stealth, Oliver 5.85 billet rods, BME nitrous pistons / CNC LT4 heads / Comp Cams custom solid roller / TH400+GearVendors OD/4.11's / Strange 12-bolt / 300-shot N2O / Spohn Suspension / 6-pt roll bar with integrated SFC's / full AutoMeter instrumentation / MoTeC M48 Pro engine management system / a few other odds 'n ends. 800HP/800LB-FT at the flywheel.