Wheels - What will fit??

[jwbchevy502]

I have a 1968 C10 I am finishing up and want to go with 18X8 or 9" wheels. Any recommendations on what will and what will not work. I have 6X139.7 set up and am hoping someone can guide me on Manufacturer as well as what the max setback I can fit on the stock setup. I have 21/2" drop spind;es on the front and a 3" drop in the back from CPP. Looking foe a black wheel if possible. So far all I have found is a 5.09" setback which seems like it should work without interference but would like to reach out to the flks that have experience here. Any help woud be appreciated.