Ok Have had these manifolds on my fresh water motor now for a few(3) years here in the short season of boating in the Chicago area. They where on the boat for an unknown amount of time on the boat when i got it. We are planing a move near the Gulf in the next few years and want to get this thing set up for it .I have a heat exchanger and plan on installing for the summer(1/2 system). My questions is this....
1) How can i date these things?
2) What is the life expectancy of these manifolds in salt

I have used them in salt water and they were still good after 6 yrs. I
wouldn't worry about the salt water as long as you flush them everytime after use. Tom

mine are from 94 good as new boat only sees salt water there 12 now hope to get another couple yrs gee is this a record

as long as you flush ( and dont pee on the seat ) your ok

flush with fresh water and use salt away once in a while esp before winter lay up