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

I feel that there are too many variables to compare here. The 340 block is better, the crank is better. overall the engine is stronger and better built. Not that the 318 isn' t a great engine, but it was installed in a few million cars and was quite generic. Every 340 in the world came heavy duty and from a valuable collectible car by todays standards, regardless if they are still in the original car or not. The 318 will always will be the the poorer cousin and will always come out on the short end of the stick. so the 340 is more desirable, and always will be.
a bit like 440 guys pissing at each other that the 440 HP block is worth more and better than a regular 440 block. another senseless comparison.

in the end the fastest of the two depends on how much money you throw at it.
Like matt Dillon on Gunsmoke said:"There is always someone that will be faster"