Most often it is not the needle & seat that fail, it is the o-ring!
Genuine Holley QFT AED CCS 6-504-2 .110 Holley Needle and Seat Sold as Pair
Holley Needle and Seat Gasket Nylon Bottom / Top Holley Carburetors Kit 10 Pair
10 HOLLEY NEEDLE AND SEAT O-RINGS, AED BG DEMON GRANT QFT CARBS
10 HOLLEY NEEDLE AND SEAT GASKETS, AED BG DEMON GRANT QFT CARBS
Holley .110 Needle and Seat Fits most 2300-4500 Series Holley Carburetors PAIR
Genuine Holley QFT AED CCS 6-518-10 - (10 Pack) Holley .120 Needle and Seat