hose size for supply and return for heater core

Hey all do any of you have problems with the return hose that hooks to the top of the intake manifold. On the small block the nipple seems to be alot smaller than the hose so do any of you know if the return hose is supposed to be smaller than the supply hose? Do you guys know what size hose you are supposed to use?

Pat Faley
1967 Barracuda NB
Peoria IL