I am swapping a 518 OD in to replace a manual, and bought a 14,400 BTU B&M SuperCooler, but it uses 5/16" hose barbs. Is this going to be a problem? I have read 3/8" lines are important on the 518.

If the 518 needs the flow of the 3/8" lines, then this could be a problem. But if the 3/8" line is more to deal with the inefficiency of the stock, radiator based cooler, will the more efficient B&M cooler be fine with the 5/16" inlets? I can even run 3/8" to the cooler, bought a 20' roll of tube already.

For what it is worth, I have already added a deeper aluminum pan and a Autometer trans temp gauge sender into the pan. So I will know if there is a heat problem, but i would rather head it off, than fix it later.