Edelbrock 1910 CFM

[72cheyenne]

Hi,  what causes the Edelbrock 1910 to have 850 CFM when the size of the openings look the same as other Quadrajets with smaller CFM?  I also hear people say it is too big for a high performance 350 cubic inch motor and only can be used on a big block.  I plan on using it on a ZZ4 with headers and a high flow dual exhaust (3.73 rear end).  Seems to me the only issue would show up when the secondaries are opened up.

Thanks

Bob

[429bbf]

bob you can tune a 1910 to run on a 305 chevy. i think the way they got 850 was by opening the rear flap further and maybe cleaning up the castings. i noticed the on the one i have the secondaries open to approximately 1.260 . fwiw

[72cheyenne]

Thanks, that is what I suspected. 

[72cheyenne]

Here is something I found on another chat group:

Since you don't have any A/F ratios to play with, we're shooting just a bit in the dark, so any changes made need to be a little bit on the conservative side to keep from "overshooting" the mixture.
The stock jetting on your 17080204 carb is:
71 main jet/42 Primary rod/"CH" sec rod (.057")
This produces cruise and WOT metering areas of:
2.57/3.43 respectively.

As a first step, I would change the primary metering to a 73/44 combination. This will bump your metering areas up to:
2.66/3.65 combination.
This richens you up 3.5% at cruise and 6.4% at WOT. If this makes the engine respond better, and you're headed in the right direction, go to a 75/46 combo. This will put you at: 2.75/3.88
This is a 7% & 13% increase respectively, and should put you solid into the 13:1 range at WOT.

As a final tweak, pull out the "CH" secondary rods and drop in a set of "DA" rods. The DA's are .044" diameter compared to your .057 CH sticks.
This should give you a bit to play with and get you in the ballpark with throttle response and power.

[Cliff Ruggles]

Mathematical formulas are only good for Internet discussions, at least when it comes to changes A/F proportionally at any engine speed/load.

There is a LOT more going on with these carbs than just jets and metering rods.  The airbleeds used in each carburetor have a MAJOR impact on fuel delivery to the engine.

The 17080204 carb, for example, is a large MAB model.  It will be pretty lean with small jets in it.  The same basic carb used years prior came standard with 76 or 77 jets in it, and typically 47-49K metering rods.  They were, and are very lean on the primary side everyplace.

The 17080204 with 73 jets and 42K rods would be OK, but the "K" rods don't offer enough range on the upper section to get enough fuel to the engine at part throttle.  With "P" series rods it would work a lot better. 

The made several different types of metering rods for those carburetors, J, K, L, M, and P's.  The all fit, but not all of them will provide the same range of adjustment via the APT system.  The "M" series also has .036" tips, and best used in the SMAB models, not the large MAB carbs.....Cliff