oil leak on 59 A

[trucker 46]

Rebuilt and had rotating assy. balanced on my '46 1/2ton Mercury. Have to leave country for several month, before I had chance to install the engine.
Primed the oil system with non detergent motor oil and fill the crankcase with
!0w motor oil up to lifter level.
My question is: is it normal to have oil drip from rear main seal area? (brand new Fel-pro rope seal).