The thing is you don't want a Tee at all off the block. You want a fitting that goes to a line that goes to a tee on the firewall. McMaster Carr is ur friend. I put all my oil line stuff together for like 50 bucks... sorry stevemode. :P

 

easy out kit bottom line, possibly try heating the block up too, since the aluminum should expand faster thn the brass.

 

Listen to this guy he's right. Dont put a T on the block next time. Put a line to connect to the T, and mount the T on the firewall. It's safer that way.

 

And if you insist on using an NPT fitting hanging on by 2 threads, at least run a 1/8 NPT tap through the hole so you can thread it in all the way.