Edelbrock Carburetors?

Ding Ding Ding Ding, Winner!

Power Mode: Lean.
Cruise Mode: Seems about right.
Idle: Tuned to 12.9 ~ 13.5. It jumps around continuously.
WOT: Didn't even attempt it. Too lean during Power Mode, so I was not excited about what might happen at full power. Gonna richen power mode and try WOT only after that.

First thing I'm going to do is put a firmer step up spring in it. This would pull the rod out of the main jet at higher vacuum levels (than the current one), bringing on the fuel sooner. If that doesn't richen it up enough, then I'll consider rods / jets.

But the one thing guys complain about on the Edelbrock quite commonly, I see this problem also. Just after consuming the pump shot, it goes too lean. Even at max pump shot, it still spikes lean. And can lead to a stumble. Mine did this on the 1407, and is doing it on the 1405. For those without an AFR, this happens at about 1.5 seconds after beginning to accelerate away from a stop.

I have a theory on how to improve this. The theory is this. What if the "step" on the rod were higher up on the metering rod. Higher up meaning closer to the bend in the rod. In this way, as vacuum is lost on an initial acceleration, and spring begins to lift the rod out of the main jet, the step arrives in the main jet sooner. And thus more fuel, thus no lean stumble.

Does anyone else think this might work? I could *possibly* have some custom metering rods machined to test this theory.


7milesout

That is exactly what mine does on the pump shot, but not too bad.
I do get an occasional stumble if the engine isn't completely heated up and I can watch it go lean for a second.
Changing where the shoulder is might help, but I just opened the squirters a bit larger and it helped but the pump total volume is really the problem .
It was a better alternative than always running too rich to solve it though.
At one point I even considered a custom added shot on tip in (like and injector), but I didn't do it because of the injector would need a lot more fuel pump pressure and the whole thing didn't seem worth the trouble if we could just change carbs to something more suited.