Quickest/fastest quarter mile on 15 inch "cosmetic" all season tires like BFG T/As (etc)?

Another factor I haven't seen mentioned yet about the speed rating is in relation to weight load and tire pressure. You can read on the sidewalls of modern tires "Inflate to XX psi MAX at YYYY lbs max load". Our A-bodies are pretty light and typical 9+ inch-wide 60-series tires can usually handle at least 1.5x (probably closer to 2x) the load that our cars put on them.

That's why you can technically inflate a tire well over its "max" rating and it won't explode... unless you run it on a heavy C-body or truck and cruise near the max speed rating for a decent amount of time (much more than it takes to run down a 1/4-mile). Running at lower pressure heats up the tire faster due to more tread and sidewall deflection as it rotates but again over the course of 10-15 seconds that's not a whole lot.