edelbrock carb tuning?

I don't mean to hijack SirDan's thread but I have basicly the same problem with a 273 I built. Lowcompression pistons, .030 over, mild solid lifter cam. I have a new 1406 and it dies at about 2500 rpm until about 3000 rpm. Tried changing springs and it didn't help. 18" of vacuum @ idle.