Thanks for the feedback - the builder dynoed the oil pump before he installed and said the relief valve opened at 55 psi. Definately not the case now - went easy on it this time after checking the filter adapter and it would crank to 120 psi no problem - holy crap when I saw that.
Dropping the pan tomorrow to pull out the relief valve and flush the pump and double check it before reinstalling.
Makes me worry why it was intially okay but now it is not.... should I just replace it with another new pump or if the valve is free and we flush it no worries I guess?