Why does it seem all ports even super serious max effort unlimited buget, are either rectangle oval square... but never a perfectly round port? Seems with the biggest cross section VS surface area it would make the most flow... just curious what I am missing there.

And while I am wondering hypothetical curiosity stuff why not header style intake mainifolds like toyota corllas? With modern MPI it seems the problems of the long ram BBs fuel pudling/dropout would be long gone...

Ford did big round ports on the Tunnel Port 427. They didn't seem to catch on.

Round doesn't seem to work very well on the intake side, at least for wedge heads. Maybe it works on OHC type of engines. Round seems to work on the exhaust side. My guess is that it is as much a packaging problem as anything. They might want to use round on the intake but the pushrods force the shape into a rectangle.

I think like Andy said port area becomes an issue. I know Al M has posted pictures a few times of his oval port B1 heads and they put out some nice numbers.

Apparently air doesn't flow efficiently in a round tube I've been told. Creates a vortex and turbulence.

Kevin

Think about a round layout in a head.... with 4 ports in a single casting; round next to round, you’re giving away a lot of available space that could be flowing air, and instead is carrying weight.

If you go look at some high performance OHC heads you'll find round ports. Some Porsche heads used round ports on the intake side for example. You just don't see it with wedge heads except for the 427 tunnel port. The Boss 429 has round ports on the intake side.

There all fluids, correct, air or liquid
Think about water flowing down a drain tube or toilet, doesn't it swirl as it enters the smaller part of the tube, venture, or exit
That being said every production 460 Ford head and 351 C motors had round ports in them, correct

From the web:

"Big-block enthusiasts have always looked down their noses at oval-ports, but we’re here to tell you that round is the new square. As a general rule, round (or oval) ports will outflow their rectangular counterpart given equal dimensional area. The reason is that the corners of a rectangle are actually wasted space in terms of flow. The flow rate in the corners is very limited, so the wasted space does little more than increase port volume. This is obviously not a desirable situation, as power production is a product of both airflow and volume. The ideal situation (for most street/strip motors) is to maximize flow while minimizing port volume. There’s an argument to be made for increased port volume on high-rpm (dedicated) race motors, but for most, small port and big flow is the best combination."

Kinda, sorta round if you remove the fins (to meet a volume spec for NHRA).

round ports seem to work.
https://bangshift.com/bangshift1320/1200hp-naturally-aspirated-pontiac-horsepower-dyno-power/

I bet the whole arctitecture of most heads are the limitation,there are headbolts and pushrods getting in the way of the ports.

Ever look into a new style 350 LS1 Chevy head? Kinda like a tall bullet, not square or round. Last time I looked they make a lot of power.

As a general rule, round (or oval) ports will outflow their rectangular counterpart given equal dimensional area.
Or, not.

If it was that obvious, why do those idiots continue to design ports in other shapes?
Because the port is NOT STRAIGHT.