Not all Quadrajets are the same. SMI is a company in California that can fix your carb. Stands for Sean Murphy Induction. www,smicarburetor.com He can help you. He's in Huntington Beach 714-843-9169.
If you don't like what they have to offer.
www.Cliffshighperformance.com can selll any AND ALL parts, kits you need to do it yourself. Not sure if SMI sells kits, etc...