Yes, guys, those are my two choices--temp sensor port and stop cock drain plug fitting. Unless I'm missing something, when using the Langdon fitting plate, there appears to be only one extra outlet available at the front of the engine.
On the 261 in my '56 I ran the rear water heat line to the two brass temp sensor blocks at the rear of the head. (I have two because I have a functional gauge on the dash and one below the dash in a little gauge cluster.) I used brass blocks with double inlets so I had the depth necessary for each sensor, realizing that because both gauges are outside the head, they would always read a little on the cool side. That's why I'm wondering about using the stop cock drain plug as my return access. It would be a lot cleaner (and easier) installation. As I plan to use hoses, I don't like the look of running a hose completely around the back or front of the engine with a "T" on one of the heater hoses.
