Anyone install a heater/shower with a mercruiser mag engine? I have a heatercraft heater and shower that I need to install and need some help locating the best locations to tap into for hot h2o and the heater return. Below are some pics of possible options for my mercruiser mag engine. I've considered splicing into the water line between the vdrive and impeller housing for the return, but can't locate any 1 1/4" t-fittings locally. The plug in photo 4 seems a likely option for the heater hot water (3/8"), but the plug in photo 2, I can't figure out what size it is. Neither my 3/8" or 1/4" sockets fits....and I don't think they make a 5/16" drive...