10 sec. 318?

I know I'll have to end up doing something with the rear suspension at some point, the old spring seem to drop mighty low... I was going to trow a set of air shocks in for some fun to get the rear end up and looking good, possibly a set of traction bars or something at some point, need to move the springs in first. Right now debating on how far I want to move them. I'm really not a welder and don't want to cut up my frame rails, but I don't think the 3/4" offset kit is going to do much for squeezing in bigger tires. I know I'll have tub issues at some point as well, but I think I can use more of the tubs with a frame mounted spring than an offset mounted one. I'm thinking 275's for the tires, can you go any higher with frame mounted springs and no tub work (aside from probably rolling the inside fender lip)?