not that I don't believe you but care to share where that kind of money goes?? even with aluminum heads, I am not sure where the thousands and thousands go???
As to your question of why the factory didn't do it.......as already stated , they did. A 318 is a stroked 273. A 340 is a stroked 318 with a bigger bore. A 440 is a stroked 383 with a bigger bore. I know. The "correctors" are fixin to jump on. But I ain't talkin about the B 383. There was a seldom talked RB 383. You can pretty much divide Chrysler engines up by stroke if you look at it. All the other manufacturers did similar things. Chevy started with the 265 small block that eventually evolved into the 3.75 stroke 400. They went all the way with that one. I wish Mopar had.