What size tire on a 7" rim.

[rs74]

I have a set of 7" & 8" rallies and soon to be two short beds. I want to save the 8" for the one that I am rebuilding. The shorty that I am getting needs a set of rallies back on it and if I can't find a decent set of 8's then the 7's will go on. My question is that I was thinking about either running 275/60's all the way around or maybe 245 on the front and 275 on the rear. Will a 275 go on a 7" rim? I really like the fat tire look on the rallies. Right now the truck is stock height. At most if I decide to lower it would be a 2/4 drop.