the front rims are original, so I do not know their offset - however they came from the factory. They will barely rub the frame at full lock.
The rears have 4 1/2" backspacing.
Clearances in the rear should suffice (fender lip to tire)...i had 3 neighbor kids in the back seat, my wife and 2 daughters jumping in the trunk while I had my hand on top of the tire between tire and body lip - my hand never got cut, so I will assume it will be ok. Approx 3/4" to 1" clearance to leaf spring. But this is with 65~67 B-body rear end and offset shackles.