On my 74 I have 15" x 8.5" wide Rallyes (custom widened) and run 275/60/15. Stock height suspension. There is about 1/2 inch clearance to the leaf springs and probably the same clearance on the fenders. Nothing rubs and no "massaging" of the fender lips were required.
I have heard of some fitting 295s but due to how close mine is inside and outside I would question it would work without a little trimming. Do some measuring on your car to be sure what can fit. No two of these old cars are exactly the same. There could even be differences between the left and right sides of your car. Remove both your rear wheels and support the car on stands from the axle (not the frame) so it is mimicking ride height. Also no air in shocks. They can force the car to lean left or right which can throw off correct measurements. (Also as noted earlier please remove the air shocks they eventually will do structural damage). Use a weighted string and drop a line from your axle mounting face for the wheel and mark a spot on the ground. Do the same in several places along your inner fender lip. A few spots fore and aft of center line to what would be your tires diameter. Also measure location of leaf springs. Be sure to measure fore and aft of the center line on these as well because I believe they are not parallel with each other.
Throw a tape measure on the drop markings and you now know the real estate and offsets you have to work with.
Fronts are 15" x 7" with 215/65/15s on the. IMOP i do not like how these look and will eventually be going at minimum 225s on the front.
One recommendation is to go with 15" or 14" rims on all 4 corners. Not a mix of both. I also believe you will find many more tire size options with the 15s. 14" rims are old school and are becoming more limited in availability.
Good luck with your decision.
Mike.