17x8 wheels, will they fit?

[kanuck]

just went and looked at set of 4 17x8 chrome wheels that i can get for $80 bucks because the chrome is pealing on all 4, no other damage otherwise.
The bolt pattern is right at 5on 5 and the label gives the offset as +18mm.
Think the name on them is cheyenne.
Measuring at the back of the rim I got 5.5 inches from the backing plate to the outside of the rim.
Wondering if anyone knows if these will fit on my 1984 swb lowered about 3 inches in front. Seems like a fair bit of offset and wondering if they will rub on the inside.
Also will the chrome come off with sandblasting? Was thinking of powder coating them if they fit the truck.
Thanks