can't get idle lower than 1000

You need to reduce the size of the idle air bleed. I explained it in an earlier post.

When you look down the top of the carb you see along the front edge of the venturi inlet two small jets for each venturi. The inboard ones are for the main metering circuit and the outboard ones are for the idle circuit. Most Holleys will have a .070-.080 orifice in the idle air bleed. You need to reduce the size to about .040 by either replacing the air bleed (you can buy air bleeds from BLP or similar carb shops, try a Google search) or just putting a dab of Devcon F epoxy (the black) on the bleed, pressing it into the hole then letting it cure 24 hours and redrilling it to .040 using a drill bit that size and a pin vise. I'm sure Jegs sells small carb drill bits.