Yep bigger tires are 1 benefit, but if ya add solid bushings and new springs and frame connectors its a big difference to stock! Did it on my 66 and i can run 15x8 rim with a 275 tire with no rubbing, Here's a pic with 255's on a 15x8 rim.
I do plan on installing frame connectors, keeping the springs that are on the car, but I guess I can say I never heard of solid bushings. I like the look of the wider tires!