Is my oil cooler overkill for the street?

RegPei

I've always thought the reason you don't rev the engine when the oil temperature is cold is due to the high oil pressure this would result. The higher the viscosity, the higher the oil pressure will be for a given RPM. Higher oil pressure can pop oil seals/gaskets and those lines to/from your cooler.

At the bottom of the oil pressure gauge DIY, the OP mentioned his observation after installing the gauge:

DIY: Oil Pressure Gauge

So the key at the low temperature end is less oil temperature than oil pressure. If you really need to stomp on it going an average of 15-18 MPH (5-6 mi in 20 mins), you could in theory switch to a lower viscosity oil just to be safe or get an oil pressure gauge.