70@idle would be unusually, and unnecessarily, high. I assembled a 340 engine about 2 years ago, that seemed to have excessive oil pressure like that.I told my employer lets get a second opinion; a second gauge. Well he insisted his gauge was accurate. Well he had me running around in circles for several hours, and he himself spent more hours on it. Turns out, his gauge was NOT so accurate after all. I quit shortly afterwards when we butted heads on another project.
I'm not saying I'm the smartest old-guy alive; Just that a second opinion was a no-brainer.
I'm also not saying your gauge is a lying, just that 70@idle begs a second opinion,cuz I don't think it happens for real all that often, in an engine built with street specs..