By any stretch of possibility, is it possible it still has the Berkeley nipple in the suction piece of the pump with the 1/4" hole?

Almost betting it does. In which case, it will work great.

GT

where would i find this? got a pic of one?

I think they are both there cuz someone wanted the comfort of the relief valve set up (that I kinda favor in case u didnt read the most epic thread ever) and the good ole tried and true Gate that GT prefers. 

I mean hey screw it u cant go wrong there.

 All BS aside any idea what pressure that RV is set for.  Any idea how open or closed that gate is.  Make a witness mark then keep track how much u turn it closed then write that down for reference then open back to where it was.  Then get a gauge remove inlet into ur motor use ur house garden hose and see what pressure that RV opens.

Im wondering if they were trying to control temp with the gate which is killing the water flow in reality.  Thats another story Im just talking out laud on the two valves. 

Our temp and pressure is variable and in random order.
Just the way I like it. 

Now for a serious question..... oh never mind.