at 375degf a 1 lb meatloaf will take about 25 to 30 minutes for the meatloaf temp to reach 160degf. a 2 lb meatloaf will take about 40 to 50 minutes for the meatloaf temp to reach 160degf. a 3 lb meatloaf will take about 1 hour to 1 hour and 15 minutes for the meatloaf temp to reach 160degf.