High idle

VonCramp said

Shaft broke due to one of the hold down bolts coming loose and since shaft is hardened steal, it broke instead of flexing.Ok I see The carb is a Pro Comp with idle screw turned to where there is no opening of butterflies.

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Well if the curb-idle screw is fully backed out, and the primary butterflys are fully closed........you have to ask yourself where is the engine getting the A/F charge to run at 1100,even if only briefly. It then becomes apparent why it takes pumping the pedal to keep it running.
If I had to guess, I'd think the secondaries are hung open.Get them closed up, then crank the primaries open until the lowest part of the transfer ports look like a little square from the under side of the butterflies. Then set the mixture screws to 1 turn out. Then make sure the float level is bang-on. While the carb is off, check the base gasket, and the PCV hose for cracks or splits.