Front port is the discharge into dry sump tank from scavenge stage of the oil pump (front section of the pump) should connect to top of aftermarket dry sump tank, the rear port is to the inlet to pressure side of the oil pump (rear section of the pump) connection should come from bottom of the dry sump tank also, the drain plug for the dry sump tank on the LS3/7/9 dry sump pan (output of pump pressure stage is to the block of course.) I port and deburr all my LS oil passages on motors that will see extended high RPM operations.....GM does a HORRIBLE job of drilling oil passages and deburring oil entries into oil filter mounting area.....just DAMN AWFUL! I have hand ported GM pumps and Katech CNC ports their high volume oil pump offerings.
Here is a link to some LS7 stuff:
http://www.camarohomepage.com/ls7/