I found a shop that could weld cast iron and I dropped off my exhaust manifold. They called back a day or two and said they couldn't do it. I ended up with this:
IMG_0991.JPG
I didn't have the patience to see if the engine would start while I was hunting down a replacement exhaust header, so I finally hooked everything up and gave it a try. And here's a video of the first go:
http://youtu.be/6dlgdsIRzdsYou can hear the loud popping since the exhaust manifold has a big fat hole in it, but at least it runs. I'll have to admit that this was music to my ears, having never completely rebuilt an engine before!
At this point, I re-installed the fan, fan belt, alternator, and radiator hoses. I finalize the wiring to the alternator, temp sensor, and oil pressure sensor.
My machinist came over to help me do some basic tuning, set the timing, and properly adjust the valves. He also strongly advised against running the engine any longer than necessary until I had an exhaust manifold in place, due to lack of back pressure. We did have trouble keeping it running, but until I was able to track down a replacement, I was stuck.
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