Misfire Question

[1979AJ]

Hello, im new to this forum. I have a brand new chevy 350 crate engine with a new HEI distributor new plugs new plug wires edelbrock intake but kept the same rochest 4bbl quad-jet carb. The engine runs great at higher rpm but seems like it has a rough idle almost like a misfire at idle or low rpm 650-1000. Im stuck and don’t know what to do. Thanks in advance