The timing cover does not necessarily align properly on the dowel pins, leading to distributor to cam gear alignment/binding issues, and possible consumption of the distributor gear.
Skillful use of a mallet is a prerequisite to proper AMC assembly :t:
RE: Oiling system - not really necessary to get too wrapped up in mods of this nature. If you are using stock type non-roller rockers, sufficient oiling to the top is necessary to cool upper valvetrain. In short, you probably do not need to worry about restricting oil flow to the top if extended operations above 5000rpm are not anticipated.
As Jeeps4ever has advised, proper pump setup and increased pan capacity are probably all you need to pay attention too.
Check pump pressure plunger for free movement - especially if you get a new filter adapter.
Learn all there is to know about the way oil is routed to the timing and distributor drive gear and make sure these paths are aligned properly and not blocked by a machining burr or other such dumbness.
Index mill the decks for .040-.050 piston to head clearance, bore and PLATE hone cylinders (Bet you machinest does not have a AMC torque plate).
Make sure the block is clean, clean, clean. Then clean it again.