I've been using 15''x10''s that had a rear spacing of 4.50''. But now, I have some new 15''x10'' wheels with a rear spacing of 5.5'' with which I use a 1/2'' spacer.
15x10 5.5 bs with a 275/60 will work on a stock frame car. Frame centered under car. Fender lips will need to be trimmed and the car cannot be too low.
That's exactly what I have (15''x10'' 5.5'' rear spacing and P275-60-15 tires)...In fact, it's my new tire/wheel combo. I'm using a 1/2'' spacer on both sides because the frame is still stock, but next year, I plan to have the frame notched and then I will remove the spacers and I'll be ''in business''!