Thank you for fast response. I consider this an upgrade to the E35's as they are a pain to change impellers but Crusader's company folks said don't use them! I originally put the F6's on my engines, twin 270's with front mounted 1/2 system cooled and Barr center riser manifolds and at high RPM's the pressure blew the end caps off the one old heat exchange with rubber end caps destroying the last spare I had. The old end caps are NLA so I had to replace the old heat exchange with new. Fire engines up for another shake down cruise and a hose blew off outlet hose on the pump. After researching the gallon per RPM charts apparently the F6's pressurized system too much at high RPM's. I just finished the repower and working out issues and this hopefully is the last! If I had the money to put into this old boat I would have preferred to go full system with Crusader style manifolds but she will be fine replacing exhaust manifolds every four years. Building raw water cooled engines or even 1/2 cooled system is BS in a salt water environment. I don't know why boat builders do this other than being cheap.
