You need a smaller carb prob. I run a 650DP on mine. Is it a built up motor? Give some specs on your vehicle, transmission, ratio, and what it is in.

 

QUESTION How do I tell what size carb I need?
ANSWER You take the engine cubic inch and multiply by the maximum RPM and divide by 3456. If you have an automatic transmission you will need a vacuum sec. carb, a standard transmission can use a Double Pumper carb.

thats straight from the holley website. A friend of mine tried putting a 750 on a slightly worked up 350 and even after jetting it down, changing pump shots and pump cams we never got it to run right. he swapped to a 650 and it ran great. Im sure thats not what you wanted to hear but I hope it helps

 

I Got A 750 Holley On My 350 Sbc. The Plugs Are Black And Smell Of Gas. It Had 72 Mains In It. I Put 70's In It. Should I Go Lower Like 68's ? I Am Going To Go From Ac Delco R44 To R45 For Plugs. Also I Cant Seem To Get Rite Adjustment On The Screws. If I Twist Them In It Has Minimal Effect On Stalling Out. Thanks For Help, Gary

This same thing is seen here on a constant basis.

This is a case of the ignition being the cause of a carb "problem", most likely- and the non responsiveness of the idle screws is the clue (providing the carb is in good shape otherwise, and does not need rebuilt).

To start with, you need to provide us w/ALL the specs that you possibly can, w/regards to the engine and vehicle and how you plan to use it.

Most likely, you need to get the timing curve worked out first, then the carb will follow. A 750 vacuum secondary carb like the 3310 can work fine on a 350 cid engine- BUT it takes the correct tune to do it. A 4779 will take some doing, and really, I wouldn't recommend it for a mild 350 in the first place.

AFA jetting goes, need to know what carb you have- the number is on the choke tower or carb body if the carb has no choke. At least say if it's a vacuum secondary or DP.

 

rejet holley

its a 4160 750 vac. secondaries not a dp. the motor is bored .030 dont know anything about the cam.(i recently got the car).i am in process of changing heads. it had 307ci heads on it,im putting 350 heads on it. it had a single plane manifold im changing it. thanks gary