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

Well, once again, you left out the 360, which was produced from 71 till 93, far outpacing the number of 340s out there. A REAL budget hotrodder is gonna choose the equally cheap 360 core...not a 318. It's a skewed argument, with unrealistic limitations on what's available in ANY wrecking yard.
Of course, and this was said from the get go (by me and a hundred other posters...) and the reason "why". A 300 dollar 360 and 2700 to throw into it kicks the living snot out a 1500 dollar 340 with 1500 to put into it. Is that light to a dark world?????? Now, when you bring in the 318, it's a new discussion. I cannot figure for the life of me why this is hard to understand.....