Finished the clutch. Thanks to all who commented and left many great tips. I ended up LIFTING the transmission and putting it on! Nothing subtle. All those visits to the gym finally paid off.
I have an odd problem. When the car (1993 Civic CX) sits with its nose even slightly pointed uphill, it won't start. The second the nose points even the slightest bit downhill, it fires right up. I'd like to avoid dealing with the fuel pump, of course. But, after the clutch, everything should be... downhill, right?
In the no-start condition, can you hear the fuel pump prime for 2 seconds when you switch the ignition on?
You remembered to reconnect the engine wiring harness ground to the thermostat housing, right?
It's just such a weird, intermittent problem. I keep forgetting about it. Why would the car only fail to start when sitting nose up? If I am sitting at a light with the car running nose up, it doesn't stall. Guess I'll replace it, I have to take the whole rear interior out anyway (badly run speaker lines).