My friend has cmi headers but never flushes his out at the marina until winter. this will be his 3rd year this spring how long will they last, my S/M will be 13, but I flush them out we are in salt water.

Salt water and he doesn't flush!?!?! He can expect 3-5 years then they're probably going to get close to failure. Salt gets very invasive when heated to over 240 deg. If he leaves salt water in his headers and parks the boat they are going to get up to that temp easy.

What the hell, headers a cheap right?

Considering CMI has a one year warranty, he needs to take good care of them. If he does, he'll get some time out of them.

I told him he needs to flush them , he just brings it back and shuts it off at the dock, this fall the dart intake I sold him 3yrs ago went south ,and he was gee you sold me a warn out dart intake. noooop I said you don't flush it two yrs ago it was valve guides on my old heads he ran them 2yrs want me to pay again. they were nice heads with port work valves springs I sold for 800to him. I thought that was cheap they were set up for hdy roller cam. man I hope I'M NOT WITH HIM WHEN THEY GO . i AM GOING TO TELL HIM TO READ THIS maybe he will get it. and start flushing

Sell him a flush kit and a garden hose !!In my opinion, maintenance is an enjoyable part of the hobby.

The best and most expensive parts will only go so far without regular maintainance. A little care goes a long way with a boat.

The guy needs to get a clue. You cannot let metal parts soak in salt water...he knows that.

When he's ready, we'll start shipping to him annually!!