Running great one day and next it stalls every time I hit the gas too hard

TT5.9mag said

This is likely a lean spot caused by an accelerator pump shot gasket. I would start with the easy stuff. Set the fuel pressure at 7psi with a Holley. Make sure the float levels are set correct and pull the air cleaner with the engine running at idle, for two reasons,
1. Look for fuel dribbling from the boosters. If it is either the float level is too high or the needles have trash in em.
2. Check the pump shot. It should start to spray instantly when the throttle is cracked and you should get a nice spray out of the nozzles when rapidly opening the throttle by hand.
Both quick easy checks that can tell you a lot.

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I can't set the fuel pressure on a mechanical pump, but I really don't think it has anything to do with fuel pressure. Remember it only stalls when I wack the gas. If I go easy on it, and slowly press it to the floor the secondary's open up and away she goes. If there was any kind of fuel starvation problem it would happen all the way up the revs not just from the wack on the pedal.
I'll look for the fuel dribbling out of the boosters. Maybe all my fun on Saturday knocked some crap loose somewhere and jammed up a needle, but you would think that would bugger up the idle too.
I'm gonna focus on the pump shot, though I'm not sure it would stall. Wouldn't it just bog if there was no extra fuel squirted? It almost seems like it's dumping too much fuel and stalling it.