Went back and looked to see if I missed what you said.
Something about having a nice day???
If you have something to say that’s constructive I’m all ears, I’ll listen

I did, and its a great baseline, cubes X rpm = yada.........but a Hemi is a bit different in its air and fuel needs. I have run as big as an 1150 dominator on a 431 cube hemi on the street, and it was actually a decent carb over a bunch of others I tried. On that 431 hemi, the best setup I ever ran was a set of dual 750 eddy carbs with all the choke stuff removed on a rat roaster with a 1" lid spacer, and 1" carb spacers and all the internals modified. That was the only setup that beat the old school dommy.

An 850 on a Hemi is pretty restrictive and will actually run out of breath at 5k on a 484 Hemi. On a 440 mild stroker, an 850-950 is about perfect, but on a Hemi with heads flow typically +380cfm out of the box, its a big restrictor. even with a mild cam. Think about it, they put dual 600's on a stock stroke 426 hemi......Now a days we are putting dual 800's on the 540 and bigger hemis....They like big carbs, they like fuel, and they like air.....More than the formula accounts for.

I love tinkering with carbs on engines. I can typically find the best jetting and timing with most combo's....But for the 484 Hemi, I gave you the best results we have found with more than 20 years of messing with them. The 1050 Proform 4150 is a beast and one of my favorite out of the box carbs. We have tried a lot of carbs over the years. The only one I would like to try again somtime is an SV1.....The one I had, I did not spend enough time on it before I sold it, but I think I could have eventually got that to work really well. It showed some nice promise, especially in the idle circuit.

On anything not out of the box, I call Dominic at Thumper carbs and we discuss it. Even on my little 512 400 stroker, I think the 1050 custom Thumper dommy might be restricting us a little. Wish I had more money, cause I would have a shelf full of carbs.

We put Hemi's in everything.....Guess who gets to tune most of them....

Just a few I have had the pleasure to tune and work on...

Thank you I’ve seen the light.!

Yes, the Hemi has different demands and an 850 would be a truck carb for hauling logs and trash hell, I'm going to an 1150 which flows 1250 on my baby 470 and the last one I tested was a beast.......all this formula nonsense doesn't apply as much today imo and several who have tried my Dommy's all agree. Less is NOT more or better.....

I keep reading how certain engines need more air, etc.

The carburetor only knows vacuum. What the chamber and valve gear look like has nothing to do with it.

So here is a fact, and this happened at the drags back in 1984. A guy running a MK1 Ford cortina stick car with a Rover 3500cc V8 motor (215ci Buick), had hdrs et. etc. and a 600 Holley. I lent/persuaded him to try my modded 850DP which prob flowed near 900cfm on his car after much pi$$ taking by him that my carb was too big for my 340. And yes you guessed right, he went 2/10ths quicker, throttle response wasn't so good of course but. Why did he go faster if big carbs don't work?...............faster run was made within 1 hour of previous same conditions.

I've seen both the Buick and Oldsmobile 215 C.I.heads, neither one had decent intake ports or camshafts
My point is even a small C.I. economy deigned motor like those like more air and fuel flow for better performance at the drags

Vacuum is one part of the equation but comp, manifold, rpm's cubic inches, single or dual ALL have an effect on the needs and every time I go bigger on certain motors they pick up and some a BUNCH......

Its something to really try to understand why you get this effect. My 340 also went almost 2/10ths faster with that 850DP rather than the 750DP it came with yet I was only using around 6100rpm tops@the traps at the time on stock unported 2.02 heads and only 10:1CR, headers and a strip Dominator with 2" spacer so a nothing special motor.

An engine will only pull the air it needs with a certain head design/bore/stroke/rpm etc. yet a bigger carb always seems to work at the strip defying any method you care to use to calculate its needs. But its not always the case on a dyno, We ran a 950HP holley on a 589ci street wedge motor, only 10:1, had race heads that probably flowed in the 340cfm range@ the solid roller cams max lift of .625", and a 440-2 intake, it pulled 1.9hg vac@wot at 5800rpm and went to 2.0@6000 suggesting the carb was too small, yet when a 1050 Dominator was tried with an adapter it only made 3hp more, that could've been because it wasn't dialled in or the adapter?. but I have read a few times that on similar big ci motors of that size a Dom only made a max of around 10>15hp more if that than say a big 4150, its all combo related I guess but there is no real reason why 1 carb of only 100cfm more can make a 2/10ths difference on a smaller motor and on a large motor that actually needs at least 1050cfm+ of air according to calcs and a dyno it doesn't quite work that way, perhaps at the track it would be a different story and the better way of trying things out. Maybe things need stepping up to 2 x carbs for real gains on big ci motors with enough valve lift of course and rpm. Or perhaps my thinking is somewhat off?

sorry for slight hijack

I ran a 1050 Dom on a little 405ci small block and was gonna change to a 1150 but I sold the engine

I think it is the A/F density charge in the cylinder. Bigger carb, less restriction and pressure drop.

It's one of those things you can theorize and calculate all you want to, but real world results can and will vary.
An 850 is too small for the hemi in question here.

There is only ONE force at work in the intake system: pressure differential. Flow of any substance (solid, liquid, gas, plasma) goes from high pressure to low pressure without exception.
How it gets there varies quite a bit, but that's all there is. All of those rotating and reciprocating bits do is connect and/or regulate 2 volumes with different pressures.

There's also what I call "Frequency smoothing" meaning on most hot motors a smaller carb will be snappier and produce more vacuum across the board and unfortunately at max rpm's. By going to a bigger carb we smooth out the frequency's and like duration, it moves the power-band up accordingly and makes em easier to drive especially on the street and in a traction limited deal it helps a bunch cos I've been doing it w/great feedback from customers and my Dart loves the bigger carbs up to a point then the signal to the boosters is not happy therefore it draws more air than fuel and goes lean where a smaller carb can go rich up top because of the vacuum draw being greater(restriction).......

I thought that's what progressive secondaries were supposed to help with?

Doesn't matter if the carbs too small and my 9-second 470 HATES 4150's even 1100+ cfm as it makes it too peaky down low and will not support up top.........

....the way forward is clear for us.

Actually I meant, if the carb is too big, don't progressive secondaries help smooth out the response?
Also thinking of something like a TQ with small primaries for good throttle response, but huge secondaries for wide-open.