The last of the engine parts came in -- thermostat & related parts from Awesome Powdercoat, and the oil pressure relief valve from Tangerine Racing. Here's a pic of the thermostat installed:
The thermostat itself from Awesome Powdercoat is a very nice piece. Unfortunately, his bracket needed quite a bit of finessing for everything to fit & line up correctly. And the pulley he sells is a storm door roller that seems to be a little smaller than the original -- I had to file the cable hole in the sheet metal aft about 3/16" to keep the cable from dragging.
Fortunately, the oil pressure relief valve went right in place with no issue, once I found the tool I made years ago for unscrewing the retaining bolt. No pics of that though, since there isn't anything to see once it's all in.