Lowering question. Have a look at my pictures please.

[CPO1]

I'd like to lower the front of my 65 GMC and add disc brakes. It has 15 Rally Wheels on drum brakes. The front tire shown is a 255/60x15 and as you can see by the straight edge running up the tire side walls, there doesn't appear to be a lot of clearance. Or is this normal? If I drop the front what considerations do I need to have proper clearance?

The surface of the tire tread to the lip of that fender measures 4 inches. I believe the PO cut the coil 2 inches already



Here's another angle.


Does this look like the coil has already been cut??

Another side view


Do I need a modular drop spindle for clearance?
Can I use a regular drop spindle or Do I need to go with narrower tire like a P225?
Let me know what you guys think.
Appreciated.