Re: Innovation required
all gm blocks have drain plugs at the bottom of the block, just above the oil pan.
take the plugs out, and replace them with brass niples on both sides. run heater hose up from the niples to a Y fitting and then to a through hull flush fitting. you can just use a cap if you want, but i installed a brass shut off valve on the transom side of the flush fitting.
can use any type of pump to pump the water out whenever you want.
also great for flushing the engine at the dock when you cant take the boat out of the water for those overnighters at a sea side hotel. just plug in the hose and flush away without the engine running.
i also use mine to pump in antifreeze when the boat is not in use. then pump it out again when i want to go out, and store it.
BTW, why are you bothering with an oil evacuation system on the oil filter? all marine engines have dip stick tubes that go to the bottom of the oil pan. just pump it out there. they sell fittings that fit over the top of the dip stick tube just for this purpose.