I seen that screw set on Ebay.... Although pricey, I can justify the expense for the ease of access....

Whoever at holley designed the base plates on these carbs should be, well i wont go there..... Putting brass idle mixture screws that bust with the slightest bit of pressure doesn't make sense to me, nor does the location..... oh well, I guess it could be worse, non adjustable like a Chevy!