I'm the one who mentioned this and please note...I was careful to say "some people" and careful not to take a position. The whole idea of back pressure (in a naturally aspirated vehicle) brings along with it some complexities. Like you folks, I've heard about the need for some back pressure for a long time...over 50 years. So let's see what some eggheads think.

Here is a guy who I think breaks much of it down pretty well:

https://www.motorauthority.com/news/1114543_do-vehicle-exhaust-systems-need-back-pressure

And this guy does a decent job also:



Hope it helps. Lots of studies are constantly being done on backpressure. Here are some others:

https://www.sciencedirect.com/topics/engineering/exhaust-back-pressure

~ Jon
1952 1/2 ton with 1959 235 | T5 with 3.07 rear end