I run about a 60" long hose to the radiator on my car and have not had any problems.
I fabricated the hose out of mandrel bent exhaust tube sections and use 6" radiator hose connectors at either end. I think I will upgrade to the silicon hose the turbo guys use eventually.
My radiator does not have a drain provision, so I put a plug in the tube to drain the radiator for service.
Hope this helps,