Moving springs inboard is only part of the solution on the '66-67 B-bodies...you also have to worry about trying to get the wheel/tire actually on the car via tilting the wheel/tire and trying to stuff it in.

Stretching the panels out and narrowing the rear is really needed as well to stuff something big in there.

To get even a 275/60/15 on these is a pain...and usually means jacking up the car via the frame to allow the rear to hang as low as the spring will allow, and then also putting a bottle jack on the rear and jacking it further down.

Get If you get a flat on the hwy you are calling the Hook..