Sputtering when accelerating

[Monte57103]

I have a 1974 Firebird with what I believe is a Pontiac 350 with an Edelbrock manifold and Edelbrock 4bbl. I’ve ran several tanks of gas through it, replaced the fuel pump, fuel filter and blown out the lines. I’ve rebuilt the carb. The car idles great! When you put the throttle down, it sputters. I’ve also replaced spark plugs, distributor cap, points and coil.

Any suggestions?

 

[melsg5]

Did you also replace the rotor when you replaced the cap?
Did you use an ohmmeter to test the plug wire resistance including the coil wire?
What did the old spark plugs look like when you removed them?
Did you carefully pull out one plug at a time to see if any of the cylinders are not firing?
When you say put the throttle down, do you mean normal acceleration or all the way to the floor?
What number Edelbrock carburetor?
Not sure if this document applies to your carburetor.

https://www.edelbrock.com/pub/media/wysiwyg/documents/carb-owners-manual.pdf

 

[Monte57103]

All good questions! I did replace the rotor at the same time as the distributor cap. I did not use an ohm meter on the coil. Spark plugs were a little old but, not fouled badly.

Very slow acceleration is ok at best. Normal acceleration and hard acceleration makes the motor spit and sputter.

I’ll need to check on the carb. I am under the impression that its a 600 cfm. Not % sure.

 

[melsg5]

Check the resistance of the spark plug wires and the coil to distributor cap wire.
How many miles on the engine, if high mileage do a compression test.
You rebuilt the carburetor? If so you are sure you correctly set the float levels?
You replaced the fuel pump with what PSI pump? Edelbrock specifies a maximum pressure of 6 PSI with 5.5 preferred.