Today, dollar for dollar, is the 318 faster than the 340 ???

They did not do that JUST to the "Glory 340".

A 2.2 Shelby rated at 110 HP was dynoed at 118 dead stock. Then the Air Pump belt was cut and now it was 124HP, changed the Champions out to some Autolite Copper Truck plugs 2 steps colder and got 126, three aircleaner gaskets netted another 1 HP and final was a real good tune on the computer and it was at 129.6 HP.
While not KILLER it is still under rated from the factory.

These same mods to a stock Shelby Charger that was running 17.02 +/- .03 seconds in the quarter at Jackson Dragway SC. We went to 16.98 by just cutting the airpump belt. When all done the car was running in the low 16.80's...