hi sages- been following these excellent comments.one question and acomment. i notice both the hepu and the gmb come with two rubber grommets and a gasket with 7 holes. the big grommet is pushed into the connection to the head and the small one is for the heater pipe on the side. both appear to use a press fit connection which snugs up when you tighten the bolts. should a sealer/ adhesive be used or is the press fits dry good enough .maybe a teflonlubricant would be better when thebolts are tightened. have usually used a permatex type on other pump jobs. also do you stick the paper gasket onto the pump body with permatex too but leave the engine to gasket side dry? think the water wheel on the hepu would be better than the fan type impeller on the gmb. think of a water wheel on a mississippi riverboat. would the boat go faster or slower if you replaced it with a series of fan wheels . those with training in hydraulic engineering 101 should chime in. thanks tons olddduke