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

I don't understand the 340 envy. I also don't understand the 318 can never be a High Performance build. They are just parts. Put your combination together, and run it. If you pick the right combination and have a clear goal in mind, you should be happy with the results, no matter what block you use.
It was either AJ Foyt or Mario Andretti I forget which but had a 318 in his Indy Car with 500 HP. at one time.