[Roarvette]

The question on frame mods for tire clearance is this. All of the extensive frame mods were for other reasons.
I mounted the rear suspension which required some mods, then some exhaust header clearance was needed. An entire new removable transmission crossmember was needed with larger pass thrus for the 3" exhaust. The roll cage mounts were a modification. Everything was boxed and fully welded. It took almost one week of welding to box and seam weld the frame. The front frame horns were modified to hold the front sway bar and Ron Davis custom radiator.
The fuel cell required an entire section to be built and welded on.
The power steering pump also interfered with the cross member...
I also added a sump protector so if I bottom out I don'e lose the pan.
Here are some pictures.

As far as clearance is concerned, I wanted flared fenders so I just had the wheels custom made with the right amount of offset to clear the brakes and hug the frame.