I'm the new owner of a 220 warrior with a mercruiser 5.7L vortec. I'm new to boating, too. I had just pulled the port side head and lapped the valves, flushed the manifolds and risers. Turned it up with plugs, wires, ignition module, and rotor cap. Got it on the water last Thursday and was really happy with it! It looks like the exhaust (wire reinforceed) hoses was last replaced in 2004 - best guess by date on hose. What is the recommended replacement intervals for the hoses? I was reading some old threads where folks had replaced with stainless pipe... One thread, a fella had made Stainless tubes and surge tubes / Y pipes. What are surge tubes for? If i replace my exhaust hose, should I consider installing surge tubes? Was this a kind of service bulletin or recommendation from Shamrock? Currently, the hose is 7' long run. Thanks in advance, just trying to educate myself.