I've never seen AN-5 (or -5) ,But -6 is 3/8" id fuel line size, -8 is bigger, -10 is 1/2" id line. Your cooling system will need -8 or more likely -10 (what I use for
oil and water cooler plumbing).Figure out the pipe thread NPT sizes, get the adapter-to-10 flare fittings in straight if possible and the hose ends in the angles you need. Nothing beets stainless lines, braided and hard-polished at the carbs,with aluminum 45 degree flare fittings everywhere..