You can put an 8" wheel on there but you'll need at least 5" backspacing for it to work. May I suggest a 225/60-15 as your maximum tire size. 215/65-15 would be good too. Neither one needs an 8" wheel however.
Correct me if I'm wrong...but the reason you want at least 5 inches of backspacing is to keep the tire from rubbing the fender correct?
Adding a 3/8 spacer would be counter productive because it LOWERS your backspacing and pushes the tire further into the fender
(Now, if you needed the spacer to clear the springs...then it would work)
