Quickfuel SS 850 Mechanical Secondary for a 440

[iNTP]

The current Holly 3310-3 750 CFM run ok but stumble a bit when stomp the gas pedal.
I would love something that quick respond.

Quick Fuel SS series, 850 CFM mechanical secondary, is it too much for stock build 440?

[cudabob496]

Stumble just means your carb needs some simple and inexpensive tuning adjustments.
Could be accelerator pumps, or squirters, or vacuum secondary springs.

[Chryco Psycho]

Or timing , float level or power valve

[Moparal]

What year 440?  It will kill the bottom end some Not a good carb for bone stock,

[iNTP]

What year 440?  It will kill the bottom end some Not a good carb for bone stock,

Its 1972 440. Forged crank.

Honest I dont know what state the engine is, I only know it was complete rebuild so I take it as stock.
With the Holley 3310-3, if RPM over 1000 and I floored the gas pedal, it accelerate like crazy. From the standing point or under 1000 RPM, if I floored the pedal the engine will stumble/hesitates.

The car is about 3700 pound; 3:91 gear.

[iNTP]

Or timing , float level or power valve

Chryco, IIRC in other thread you recommended 850 CFM vacuum secondary  for a 440 auto?
What do you think about 850 CFM mechanical secondary?

[Chryco Psycho]

Should work great although with mech secondary it may stumble if you floor it at low RPM still

[dodj]

I have that carb on my 440. Great carb. Better manners than my holley 3310 it replaced.
Well, actually I have the black diamond version, but other than the coating, the same carb.

[cudabob496]

I'll guess squirter

[iNTP]

I just bought Quick Fuel Slayer 750 CFM vacuum secondary, Im not happy with the result.
With the new QF out of the box, the car run worse than the Holley, longer hesitate. But I did not try to tune the new carb, I think the carb too small and I want to return it.

I'll guess squirter

[iNTP]

What is symptoms of too much carb? smell gas, gas leaking, low mpg?

Consider it already has 3:91 gear, how does bigger carb effect high way driving? worse or better?

[jimynick]

Why not just call Quick Fuel and describe the issue to them? They're in the business of selling carbs and having a dissatisfied customer buying someone else's carb won't make them happy. As mentioned, sometimes it's as easy as adjusting the pump cam or squirter. As mentioned, a 440 will handle a 850; but on a street car running 3:91's, you'd best own a gas station if you've got a heavy foot. Try to adjust the 750 before you give up on it; but that's just my 

[stinger]

from what I understand to big of a carb will cause a lean condition,poor idle and a less responsive off idle performance. a dbbl pumper when tuned in should hit harder then a vac secondary do to the second squirter pump shop when the throttle valves slam wide open and vac drops.

[iNTP]

from what I understand to big of a carb will cause a lean condition,poor idle and a less responsive off idle performance. a dbbl pumper when tuned in should hit harder then a vac secondary do to the second squirter pump shop when the throttle valves slam wide open and vac drops.

I thought too big carb will cause rich (because not enough air to mix with fuel)?

Anyway, I ordered DP 850 CFM, its coming next week.
We'll see hows the 440 responding to bigger carb.

[stinger]

I thought too big carb will cause rich (because not enough air to mix with fuel)?

Anyway, I ordered DP 850 CFM, its coming next week.
We'll see hows the 440 responding to bigger carb.

to big of a carb will cause less pressure drop under the venturis to properly draw fuel so would run lean
any how I run a holley 850 dp with 33 squirters and pink cam up front,30cc pump,brown rear with a 50cc pump on my 440 with auto and 3:91. it will roast them from a dig but I doubt moving up in cfm will give you more low end grunt,just the opposite. good luck!