External thermostat - which port is which?

[jpaugh]

I have a 1974 911 that has the stock hard oil lines that run to the front oil cooler, stock external thermostat, but I've replaced the lines that run to the engine and oil tank with braided lines that go up and over the rear wheel. Problem is, I've had everything taken apart since last fall (engine rebuild, cleaning oil lines, etc.) and now I can't recall which line goes to the oil tank and which goes to the engine. Looking at the stock thermostat, the ports at the back (that go to the engine or oil tank) are arranged in at a 45 degree angle, with the upper port toward the back (against car tub) and the lower port is outboard. Does the lower, outboard port flow the return oil to the tank?

Teach me to not take pictures before I take things apart! Any help would be appreciated!

A picture is worth a thousand words. The arrows indicate what I think is the direction of flow:

[Chuck Moreland]

Your arrows are correct. The top fitting goes to the case, lower fitting to the tank.