If you're eliminating the factory wet cooler, I recommend a larger stacked plate cooler than the 70265, having greater heat rejection capacity, such as the
B&M 70272 (as a minimum), or the
70274 since bigger is better for improved transmission life; then plumb using seamless
1/2" aluminum tubing, the appropriate
1/4" National Pipe Straight Mechanical thread (NPSM) transmission fittings and
1/2" tube to -8 AN fittings. Read the promo from
B&M Transmission regarding their recommendations on cooler size and mounting considerations.
Since you're fabricating new lines, consider installing a
gauge manifold in the hard line for easier installation of a transmission fluid temperature gauge sending unit. Hard line can be securely anchored to the frame using
T-clamps. If you need to run the hard line through the frame rail or radiator support employ
bulkhead fittings with AN fittings to match - it provides a solid base for transitioning to flexible AN hose between the frame and body or radiator support. There are nearly unlimited configurations that can be tailored to fit your particular needs.
Edit:Use flexible hose with adequate slack between the transmission and frame to allow for transmission movement without straining the hose, lines or cooler. In addition, allow for adequate airflow across the cooler or substitute forced air cooling such as a fan.