I have a 350 bored .30 over w/ Edelbrock Performer manifold and Edelbrock 4 bbl 750 carb. Hedders, Holley fuel pump and HEI ignition. Stock cam. My problem comes in when I put the pedal to the metal. I get a smooth acceleration up to 3500 rpms and then it becomes rough and it's kind of a spudder up to about 5000. Iv'e been told it's could be my timing or that my carb is too big. Any help will do. Thx.
Update: Thanks for all the advise, it seems I have a little work to do. Thanks again all.

well i would rule out the carb being to big for sure.......being that your motor is close to stock you might be better of tho with like a 600 carb......the spudder might be a few other things.....hei modules are known to break down inside.....most experiance either they work or dont work but i have come across some that would cause the motor to cut out in the same basic rpm range no matter what gear you was in......

the other thing could be a few bad valve springs that are going into float.....they are to weak to keep the lifter on the cam in the higher rpm range.......

and it could be a fuel delivery problem as well.........this needs to be checked with a gauge while out romping on it......

could be a bad coil as well.......

someone else might chim in and give other thoughts as well......you just might have to start with a process of elimination and track down the problem.......

dd is right about this, anyone chime in.. it could be anything. Start with the basics, start with measuring the voltage to the + ignition terminal at 1500 rpms, should be around 13+.

The carb is too big, even if you disabled the seconaries, it will take that 350 to 5000 smoothly.

Front half of a 750 takes a 440ci to mid 4000 with some power.

Tighten up the secondary setting so it doesnt open as easily/quickly. Check your coil voltage. Take it for a spin. Then continue down dd's list.

check all ignition components mentioned and check your initial and total timing with a light, also make sure your mechanical advance is working properly. rev the engine up to 3000-3500 and look at the timing mark, while accelerating the timing mark should move smoothly with no pauses or sticking. if its pausing, sticking or not moving at all your mechanical advance is either frozen or binding.

if all that checks out, check the firing order and test your plug wires. if that isnt it check your fuel pressure.

i have a edelbrock 750 on the 350 in my 67 biscayne (big and heavy) and have had no trouble with it at all. i would definitely check all the simple stuff before swapping carbs etc., in my experience an edelbrock 750 works just fine on a mild 350.