I don't recall specifically what the thread size is for the accelerator pump screw but it's likely something out of the ordinary knowing Holley. The use of Helicoils in this area would likely be a problem due to the two slots in the hole that provide a path for the fuel to get to the acceleratory pump nozzle alongside the screw. I'm surprised all the threads in the body are gone though as the accelerator pump screws are usually on the short side as supplied with the carburetors. The screws provided in the Dominator carbs are typically longer though and also have a thicker head that allows for some more lengthening if necessary. The accelerator pump screws in the Dominators also have a hole drilled through their centers to provide some additional fuel flow to the nozzles. These particular screws use to be offered as an individual service part but the last time I needed some, I had to call Holley directly for them. I typically need these screws when going to pump shooter sizes that exceed 0.040" but in your case, this might be an option.Drilling and tapping to a slightly larger size is also an option but you'll need to insure adequate fuel to the nozzle as you'll lose some of the feed slot when installing a larger screw. Drilling the screw down its center similar to what was done with those on the Dominator carbs would likely get you around that particular fuel delivery issue.