The 340 is the biggest POS V8 Chrysler ever made.

That's probably a pretty accurate statement......but remember, there were many factory versions of the 350 and really only one of the 340. Man, I sure wish they had stuffed a solid cam in the 340 and gave it some real HP heads. It wouldda been no contest for sure then.
This. ..
Chevy ,I have done.. Read up on Smokey Yunich 's patch jobs on the 265 and the 283 ,for Nascar use.
Not pointed at you ,Robert..
It's just to justify what manufacturers were willing to do to win ,in the day.