273 Carb Size

273 said

That chart he's showing ain't carb size but actual engine displacement at rpm, if you put a 390 cfm or an 850 cfm both carbs will only flow what's needed, different carb size are just different amount of restriction think if it like headers 1 3/4 is less restrictive than 1 5/8. A 600/650 cfm would easily work on your engine but if your overly worried 500/550 cfm , 390 cfm would work but give up a few hp the only thing I'd put a 390 cfm is a stock /6. To me we already know what generally works no need for so called formula's. It more to match hp to cfm and matters what use a light weight deep gear high stall drag only car can get away with way larger carb than heavy high gear low stall street only car.

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Unless I'm misunderstanding it, his formula is meant to be a way to calculate the right size carb for a specific engine based on how much air it pulls at the peak horsepower RPM. He may have it wrong but his theory of velocity through the venturi seems to make since.
As he says in the video, a bigger carb can and sometimes does make since if your only at the drag strip launching at 4000 RPMs but if your mostly using it as a street car being a bit smaller is better. Yes you can go too small but you can also go too big. I don't think anyone here would recommend putting a Holly 950 dominator on a stock 273 that was originally a 2bbl and in the other direction, no one would recommend getting a smaller 2bbl for more performance.
The point of my original post was to find out what the average peak HP RPM is for my stock engine.
1965 4 dr Dart 270
2bbl
That and to initiate discussion as to how much sense his formula makes to others here. I'm clearly not an expert.
Here are a couple of other carb charts that I found.