rear tire size?

what size rear tire can i fit on my 1971 4 door nova?everything is stock.i have a set of 15x10" rally rims for it with 6" backspacing.:)

I would say it's too big, an 8" with 5" of BS fits well with a 275 60 15 and a rolled lip.

Check this out, http://www.stevesnovasite.com/forums/showthread.php?t=107616

theese rims have 275/60's on them.what can i do to make them fit?

Nothing but jack it up to the moon.