1987 Mazda B2600 overheating

1987 Mazda B2600 2.6L mileage: 150,000. I just completely overhauled the engine had it bored out to ten thousandths of and inch, put a remanufactured head on it, new pistons, cut the crank with new rods and mains. When I reassembled everything, I was extremely careful to torque every bolt to the specs that I have in my repair manual. After I got everything together and ran the engine, I found that the engine was overheating with or without the thermostat installed. I have good flow through the radiator and no leakage past the rings or through the head gasket. It is not leaking antifreeze anywhere. Please help.