I drove a friends 1968 383/auto RR that had a ton of miles & smoked like a frieght train.
It was stock, but it was very fast.
My other friend had a '68 Super Bee 383 -4speed with headers. That RR would clean his clock.
I also drove a 1971 383/auto RR that was very quick. it had 50k on it & was stock.
Those are two that stick out in my mind that ran real well.
Some 383's were just always a tick faster than most others.
Every '68-'71 340 A-Body I drove were very impressive in stock form.
No one isn't saying the 383 is a dog, just needed some of the right stuff to make it go.
One thing about it, Plymouth couldn't build Road Runners quick enough.
This may be hear-say, but I was told than the 340 & the HEMI engines were built by Chyrsler's Marine division.
Now this could make the 340 a better performing engine that the standard run of the mill 383 if this was true, since the 383 was going into a budget Muscle car.
The debate will go on.