Technical Stromberg 97 vs 48 question

Okay so my head and cam have been matched for flow.

At 9 MM lift ( yes its a smaller engine with multiple carbs) im at about 166 CFM on the intake side.

Ive read that the 97 flows around 150 - 160 and the 48s are around 175
Speedways super 97 states it flows 184 !!!
Being right in the middle which do i use ?
The heads have not been ported yet so I may be able to gain a few cfm with a decent port.

Id hate to choose the 97 and run lean at WOT, and obviously id hate to run the 48 and be too rich.
Obviously i can play with jet sizes but this being my first attempt to use these style carbs I need some advice.

Oh yah i guess i should have mentioned, im attempting to run 6 carbs, one per cylinder, i can maybe run 4 if its too much but 6 would be a much easier intake which is custom either way.

 

So, you have a 6 cylinder engine with small displacement and you want to run six carbs, each with somewhere between 150-184 CFM? Seems to me that you need to go back to the drawing board and refigure your arithmetic.

 

mmmm....(6) 2bbls on a straight six...open the throttle and it will bog from too much fuel.
^, better talk to a teacher about that math. Intake flow and carb usage are not the same.
I would use 6- 1bbl carbs, like mono jets and redo their accelerator pump circuit to lessen the fuel squirt.

 

Actually, it will bog from too much air.

 

I know IR manifold carb choice is much different than regular common plenum selection.
Okay maybe i misunderstand but why can a 250 straight 6 run 3 DCOE webers which flow approx 250 cfm per choke making about 1500 cfm total. Doing the math that means a 200 ci 6 cylinder should be able to run 200 cfm per choke on an individual runner setup. IR manifolds can support higher CFM. Maybe i misunderstand what ive read about IR manifold/carb choice.

 

OK, since you asked, engines are measured in cubic inches, carburetors are measured in cubic feet/minute. First thing to do is forget about manifolds and head flow because the best either of those things can do is get you close to 100% efficiency. An engine cannot flow greater than its size, divided by two. Your engine will flow its displacement/2 (minus losses) for every revolution. Take that and multiply it by the Revolutions Per Minute at your desired max RPM. One cubic inch equals 0.000578704 cubic foot.

For example, a 250 cubic inch engine at 5000 rpm will flow 625,000 cubic inches per minute or 361.68 cubic feet per minute (CFM). All this****uming the engine flows 100% with no losses, which is never true unless you're running a forced induction. This engine will never make use of a carburetor larger than 361.68CFM unless it revs faster. At 10,000 RPM, it will consume 723.375CFM. So, all of that being said, when you put 1500CFM on a 250 engine, it's overcarbed by at least double, and that's****uming Formula One class RPMs.