GNB Loan Bank, Grundy Center, IA Instalment Loans Business Loan Personal Loans Car Title Loans Online Loans Grundy Center, IA 510 F Avenue. ZIP Code: 50638 (319) 824-5431 Iowa, Grundy Center, Instalment Loans About GNB Loan Bank Opening Hours Monday 8:00 AM – 4:30 PM Tuesday 8:00 AM – 4:30 PM Wednesday 8:00 AM – 4:30 PM Thursday 8:00 AM – 4:30 PM Friday 8:00 AM – 5:00 PM Saturday Closed Sunday Closed GNB Loan Bank on the map Show on Google Map