you shouldn't go any smaller the -12an on any of the oil lines to and from thee pump. it has been done before with major oiling issues. search on nico club.
also i lowered the price of the oil blocks i had made.
VH45de Billet Oil Block Uses Factory o-rings for sealing to the block 2 -12an ORB Female ports 1 1/8th NPT port i just had 20 of these made i have 14 left and they probly wont last long. 200$ shipped