The oil pump chain that I got was one piece I also replaced it's small rail ,its done with the bottom oil pan off and you do most of the work underneath the car I don't remember the exact sequence but I remember that it was not too hard to figure out.

I did the whole job with out a manual which is a fools trick. As far as the front cover not going on I remember that putting the cover back on was very straight foward it should just snap roght on the dowel pins .I assume you dropped the upper oil pan a touch when you took the cover off if not that could be your hang up.how were your bopttom rails? mine were trash.....

William Rogers.........