There is a lot more to a carburetor than how much air it flows. There is also a carbs ability to atomize fuel as it enters the air stream. Thus the success of the Holley Dominators, many of the aftermarket carb guys are modifying 4150's with Dominator features to get more performance out of them. I read Engine Masters magazines because they do extensive dyno testing to verify their conjecture. I find it interesting that they can throw a Dominator on just about anything and make more power right off of idle, and many times get it to idle as well or better than a smaller carb. I went from a 850 Barry Grant to a 940 Pro Systems carb and gained so much torque out of the hole that I can break out my 28 pitch 4 blade Bravo 1 prop at will. I am seeing a lot of old ideas being discussed here. Please do some modern research. If you look at actual dyno testing, a good larger progressive linkage mechanical secondary carb will make as much power off idle as a smaller carb and will certainly make more power up top.

So, I can run a 850cfm On my 355 350 HP motor according to your points? How is vacuum an old idea? The way I see it, can't you view a carb as sort of a controlled vacuum leak?

I appreciate all the info.

Here is my question then, for a 355cu Vortec cyl, RPM Air Gap, CC XM270 HR, current carb Weber 600cfm A/F ratios dialed in. Has approx 350hp at 5100rpm @ flywheel.

What carb should I be running?


THX

1250 split Dom's on a sheet metal tunnel..

How man times you gonna ask the same question? Until someone agrees with your carb calculator?

LOLLLLLLLLLLLLLLLLLLL.

See why I said didn't want to get more involved.........

I'll stick with you for one more for some reason

Have we forgotten about the calibration part of carbs ?

If the 850 you mention is a box stock Holley, forget about it. The 850's from Holley are set up for big blocks. Typically 450hp-600hp ones.

Their is an 830 with calibration geared towards small blocks.
Don't get that one though, it's for a different application small block.

This will throw you for a loop since you are stuck on just cfm#'s and unfortunately not part #'s.... I have used and spec'd Holley HP950's for many a 350 and 383. Imagine that ? !

Guess why those work so well ?

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Vacuum leak ????

That saying is so old.

Again, air speed thru the boosters pulls fuel out of them.
Plus there are many booster designs, emulsion circuit packages, venturi vs throat vs blade sizes/designs.etc, etc, etc, that are calibrated/made a certain way to administer the correct amt of fuel for the airflow amt and properties at hand.

Speaking of vacuum, you wouldn't happen to know vacuum secondaries don't work off of intake vacuum would you ?

i would put a predator on it.

Yes ! LOL.

How about those old Pro Stock trucks ! RIP J.L.

Heres the setup you need...and yes, thats TWO blowers....an 8-71 on top of a 6-71.

Best investment I made was called Patrick at Prosystems.. he set me up with a Holley hp1000 for my motor... yeah 940+ cfm on a lil small block.

Maybe I should put my stock QJET back on ? Hehe

Mr Madness or should we call you 'Mr Go Big Or Go Home' ? - I've seen vids of your boat. Your 'throttle response' and top end are horrible................Patrick should have done the right thing and told you to run a stock 600/650 carb.

On a serious note: Just for those who don't know - mountainmadness's boat is insane for a single NA small block I/O.

Lmao not insane come on...just lil funner then stock