No hot air from heater???

[powell72]

A buddy of mine has a '67 non-air truck that he put a motor in and now the truck has no hot air from the heater. The heater worked fine before he put the motor in. After he put the new one in, including a new waterpump, the only change he made was putting the lower heater hose off the core to the fitting on the side of the waterpump instead of the intake, where it was with the old motor. The top line from the core goes to the radiator. The truck doesn't have any air pockets in it, it runs 180 degrees all day, and the heater hoses are still cool. He put a new heater core in it thinking maybe the core had a problem, even though water flowed through it, still no change. What are we missing here? It has to be pump related, wouldn't you think? We need some fresh minds on this one.