I wasn't going to put a 2 cents in, but I realized there might be a problem. I don't think the frame rails would allow much more than about 2in per side. I am thinking about a 65-66, I don't know about later years. If you look at the lower part of the wheelwell by the frame rail, I think there's only an inch & 1/2 or so you can take out and extend the wheel tub. My car is 2500 miles away so I can't go measure.
If you flip the spring to the other side of the framerail at the front, you'll have to make a bracket, not really all that difficult. The rear shackle will be more fun, I think the gas tank might be in the way..the spring would probably move in almost 6 inches each side.
I think this trick works easier on chebbies because their rear frame rails are straight, not to say it'd not work, it just might take a bit of bodging.