Hello guys,
I am new here and have a question I have been looking for for a fair amount of time.  If you have a sbc with say 400hp how much gain would you see using a set of say CMI E-top water jacketed headers.  I know dollarwise the logs are much cheaper-I just want to know the approximate HP advantage with Glenwood log manifolds, Stainless Marine center Risers (or equivalent), and a CMI Etop water jacket header.  Your input would BE GREATLY appreciated.

I found this but didn't get a real feel for the advantage HP wise you would see.

http://www.socaljetboats.com/engine-mechanical-electrical/water-injected-vs-water-jacketed/

Thanks in advance,
Scott