I am going to build up a Insane G4 hydro.I want to use Insane hardware and going to use a RCMK EVO engine.I would prefer to not use propblast but need to know if rudder style would be enough cooling?

Hello you can run the dual water pickup rudder if you have any doubts. One for your exhaust flange and the other for your cylinders water jacket. I have run a single pickup on my hydro, water enters cooling jacket first the exits into the exhaust flange then outboards hull.

Rcer

I have used all types and found they all work fine. The prop bast type can push a lot of air through the cooling system, but it will still work well enough even with full modded engines.
Hope this helps.

I agree, either will work.

Thanks for the advice. I will order just the rudder style. Want to keep it simple as possible!

Both work well, a propblast will help reduce drag if usag if used with a thin rudderblade. This setup is normally used for speed gains. A dual pickup rudder blade is another option for more water flow. We carry the propblast and the thin rudder blades at the www.redlinemotors.us site.