That Mustang pulley really cooled the '59 Fairlane 292 off but now I'm concerned that it's too cool.  Temp gauge plumbed into back of head says 155-ish, small one in the Thermostat housing says 165 while driving and idling after a 40 minute highway ride.  I'm wondering if the bypass isn't allowing the water to get warm enough to open the thermostat.  Also wondering if there is a thermostat in there.  

My plan is to pick up a 180 degree thermostat and put that in whenever I get around to it- winter time if I can wait that long.  Trying to enjoy this while I can.  

When you guys restrict that bypass to 3/16"- what do you use to make that restrictor?  Just a stainless rod?  What diameter?

I'm just worried my oil isn't getting warm enough to evaporate the moisture.  I have a temperature gun on the way so I can check it- not sure how to really do that, though or even what temperature is for oil in a non-PCV engine.  

Thanks.