Throttle Responce

[scott bush]

How do you get quick throttle response? Small block chevy with an edelbrock 4 barrel runs great but if you punch it from idle it hesitates or even stalls. Don't know what to do, What should the timing be set at? I've tried different settings but it doesn't seem to change, any help would be appreciated. thanks.

[Blue Bowtie]

I doubt that the ignition timing is the issue.

Which Edelbrock carb? They sell clones of every design, and it makes a difference. It might be a copy of the Rochester 4MV, or Carter AFB, or even a Holley 4150. Each one will have a different potential resolution for lean-out on throttle tip-in.

[scott bush]

The carb is an Edelbrock 1400 1347.

[Blue Bowtie]

I see that's the Carter AFB clone.

Presuming the float level and float drop are set correctly, there may be problems with the transfer ports, accelerator pump, throttle plate positions, and/or metering rods.

If the accelerator pump is working at all there should be a solid stream of fuel pumped to each venturi when the throttle is opened. If this doesn't occur, some investigation will be necessary to determine why. If the pump is working the linkage can be moved to provide a longer pump stroke for more fuel delivery. This alone may solve most of the problems.

If a long pump stroke does not resolve it, inspection of the main well and jets may be necessary, but if the engine run well at steady throttle the chances are that the jets are sized reasonably and are not obstructed.

Verify that all the throttle plates close equally and fully, and adjust as necessary.

Can you provide some details about the engine? What cam is installed? What are the idle RPM and vacuum readings? What is the base/initial timing setting? Does this happen when cold, hot, or both?

[scott bush]

The engine is a 307, 20 over with a stock cam. Points ignition. Timing is at 4 degrees btc. I forget what the vacuum readings were but that tested good when checked a couple months ago.