-6 x 1/4NPS is the correct size for GM turbo 350, Turbo 400, 700R4, 4L60E and many other GM transmissions. These have a straight thread and seal on the gasket. Unlike a tappered pipe thread these will not crack the case.
Package include: 2pcs oil cooler adapter ( one pair )
NOTES:: These are black anodized in color. Not for GM Powerglides.