does any one know what the part #is for stock c5 wheels and if they will fit on a f body with no mods.

 

I don't know the part numbers but they (18x9.5 and 17x8.5) will fit an F-body providing that you use stock/near stock size tires.
The C5 offset does mean that they will be a bit 'sucked in' to the wheel wells but should fit without rubbing.