new engines use oil and have increased crank case pressure until the rings brake in. The increased pressure will force oil out of the crank seals and the dip stick tube. On my engines I increase the piston to cylinder clearance and I put a finer finish on the cylinder this can slow down the ring seating but improves the ring sealing long term. There are some other things that can slow down the brake in process like a lean or rich fuel condition to thick of an oil when the engine is new. Cylinders can become glazed if the engine is pushed hard to soon. Give the engine some time to brake in and at 3500 miles try going to a 20 50 if you have not already done so and have the engine checked for proper fuel pressure at both an idle and at 2k as well as testing the emissions before the converter again at an idle and at 2k 

Bob Donalds
Boston Engine