those things will not last anytime at all if you run them in salt. The risers are terrible flow restrictions, those set ups down't make much power, but if you feel you've got to have some bling, check into over the transom pipes for them

thanks spares I haven't had a close look at them I thought they may flow a little better but your telling me they don't .I do like the look of them and the way they bolt up on the head . NOW I don't know what to do they are Horney looking

Your exhaust goes through the prop... that draws a vacuum at speed... more or less flow in the manifold won't matter and with a wet exhaust you aren't really gonna make a difference anyhow

yes its through the prop I may just buy them and try them so much better looking than the stock one , I don't like stock

remember, you will only be able to use one of those. If you want to go with better exhaust, look for stainless marine, eddie marine, rex marine, gil marine, performance manifolds that are center riser set ups, there are a ton of them out there for Chevys, finding ones for a 460 Ford isnt going to be easy. Look for something for the OMC King Cobra set ups