Post-AOS oil leak
 

Well, start with the AOS oil line at the top and the return at the bottom. Check to make sure that the oil line at the top is firmly attached and that the lower return pipe is fully inserted into the block. The lower return line is not a typical leak source since the AOS return is fully pressed in when the AOS bolts are tightened down.

Other typical oil lead candidates are the RMS, IMSB seal, spark plug tubes, oil fill tube, and cam covers. As dghii suggested, the oil fill tube is worth checking since it is right next to the AOS. Otherwise, it would be strange for one of these locations to start leaking just because the AOS was replaced.