I tried a similar approach on oil cooler hoses from a 2002 G van with a 6.5. The hoses were of similar construction. The aluminum in the hard lines is very hard, that is, it does not take a flare without splitting. I tried single and double flaring. I don't know if the aluminum could be annealed to take the flare, then re-hardened for strength. In the end, i went with all braided hose, but all of the ports on the 6.5 block and coolers were 1/2"NPT, so adapting things was easy. The radiator cooler in my M-1009 has an oddball size thread that i never could find a suitable adapter.