Harmonic balancer oil leak in magnum.

Hey everyone
I have built my fourth Magnum engine and with all 4 of them they all leak oil out of the front timing case crank seal where the balancer goes in.
I have replaced the front seal several times but they all leak. I noticed the magnum engine doesn't have an oil slinger on the crank like the LA.
Am I doing something wrong? I have even fitted the balancer to the timing case before I tighten the timing case down to make sure it's evenly seated around the balancer. Still no luck