oil leak

I recently built up a 383 and I am having trouble with a oil leak I hope you can help me with.   When  I "get on it"  traveling down the highway with  revs over 3500 I get a oil leak out the front seal in the timing cover.  I have replaced that seal once but it still leaks. The engine build up includes a Comp Cams XE268 cam, Scat 9000 Series

383 Cast Crank with 6" rods,  internally balanced , KB 164 pistons , CR of 9.6, Fluidampr #712430, and a stock oil pan .   The heads are modified Vortec with a PCV valve on one side and a breather on the other side.  Under the timing cover the 2 galley plugs are drilled with a #30 drill along with a #30 drill hole in the boss under the cam sprocket, Are these 3 drill holes pumping too much into the timing cover area ?   The transmission  is a Bowtie Overdrive 700r4 and a rear end gear of 3.36. It cruises in 4th at 2 grand on the tach and 70 mph on the speedo ,  a real nice gutsy setup, other than this oil leak out the front seal around the crank.