Educate me on why 340 fan is not symmetrical

No offense to anyone here, but I just had this conversation with the wife, it was about porting and hogging out 318 heads. I said "they'll never make them into 340 heads, its a different casting...people waste their time when they can just buy a set of heads, I don't get it. No grown man is that broke if they are building a Mopar, and these guys think they know something Chrysler engineers didnt..." I just get frustrated at the stupide' things I see ion the internet sometimes with cars. Its to the point where say you can afford a nice car, you still have to tear it down and make sure the guy before did it right.
"No grown man is that broke if they are building a Mopar" But I'm getting there quick.