Carbed 350 breaks up then clears out at wide open throttle

[thatclappedsilverado]

So thanks to the help of yall, i got the cold start issue figured out. However, now that it starts im having an issue where partial throttle is fine driving it around but if i hammer on it from any rpm other than wide open and dumping the clutch it breaks up then clears out. Edelbrock 1406 carb and summit hei. i dont have a way to properly time it as of right now but i had a guy that used to build race cars at my work mess with it and he got it running alot better than i ever couldve by ear. But its still having an issue breaking up when first going to full throttle to make a pull. I have a fpr with the factory tbi pump so i can keep my fuel return but i have no way of knowing how much fuel pressure i have. fpr only goes to 9 psi and the carb calls for 4-5 so backed it out the whole way and ran it in the whole way and set it in the middle of the two figuring it was 4.5 psi. I know its like trying to figure out a code without a code scanner but its a shot in the dark. carb seems to be jetted okay for my application maybe a tad bit big but shoudlnt affect it that much right? Sorry for the long read any help is appreciated.

 

[PlayingWithTBI]

How about your accelerator pump?

 

[dave s]

So thanks to the help of yall, i got the cold start issue figured out. However, now that it starts im having an issue where partial throttle is fine driving it around but if i hammer on it from any rpm other than wide open and dumping the clutch it breaks up then clears out. Edelbrock 1406 carb and summit hei. i dont have a way to properly time it as of right now but i had a guy that used to build race cars at my work mess with it and he got it running alot better than i ever couldve by ear. But its still having an issue breaking up when first going to full throttle to make a pull. I have a fpr with the factory tbi pump so i can keep my fuel return but i have no way of knowing how much fuel pressure i have. fpr only goes to 9 psi and the carb calls for 4-5 so backed it out the whole way and ran it in the whole way and set it in the middle of the two figuring it was 4.5 psi. I know its like trying to figure out a code without a code scanner but its a shot in the dark. carb seems to be jetted okay for my application maybe a tad bit big but shoudlnt affect it that much right? Sorry for the long read any help is appreciated.

I've ran that carb for years now on my Nova. Go to the Edelbrock site and download and read the "theory of operation". I had to read it multiple times but after reading it a few times things clicked and what I read became crystal clear. You can tweak those carbs to run beautifully if you understand them. A tuning kit for the 1406 would be very helpful. You can fine tune with the rods, springs, and if it's out a bunch, then swap some jets. And as mentioned, there are accelerator pump adjustments. Ebay has the kits for cheap. I can't stress enough to read that manual on those carbs.
If you're running a vacum advance distributor, check where you plugged the vacum hose in. I like full manifold vacum, below the throttle plates. On that carb you can use ported or full manifold vacum. I like full better.
I wish I could help more, it's hard to diagnose here on the internet. Good luck with it.

 

[Hipster]

If the timing isn't right the carb never will be. Get the tools you need to stop guessing. Timing light, fuel pressure gauge etc.

Check the initial and total timing in that distributor and re-curve if necessary. The timing has to be right first.

 

[Erik the Awful]

What does your accelerator pump shot look like?