their order of words confuse me.... the plug on the back of the block is -3....do i need this one:
http://www.atpturbo.com/Merchant2/me..._Code=ATP-FTG1

or this one:

http://www.atpturbo.com/Merchant2/me..._Code=ATP-FTG1

 

depends on what oil line you are using and what oil tree system you are using as well....if you are using -4 lines then obviously you need -4 female -3 male meaning that the male end (part that sticks out think of anatomy class) screws into the block, the female end is the end that goes in (again think of anatomy), i just got my oil lines in and i'm using -3 for the oil feed and a larger oil drain line that i will make later out of some things i pick up at home depot.

so, if you are using -3 line, then go with -3 male -3 female
if using -4 line then go with -3 male -4 female
-4 being bigger and you don't wanna shove something bigger into a smaller hole...you'll strip it

again, if you are using a -4 setup use this one
http://www.atpturbo.com/Merchant2/me..._Code=ATP-FTG1
if not, don't use either one..hopefully that answers your question

edit: only if your line has a male fitting...if it has a female fitting...use neither cus lesbian fittings don't work