Accelerator pump shot is what I would look at.
It sounds like you're using all of it before the engine gets going.
Don't know about Performer (isn't this like a Carter?), but Holley's allowed you to change the pump cam/reposition the cam to deliver les/more and affect the timing during the stroke (where the highest volume delivered occurrs in relation to accelerator pedal travel.
If I had to guess, I would think that you could slow down the initial delivery and make it last longer.
Hope this helps
