Got some catching up to do. I attempted to solder the spark plug spigot into the steel head and failed miserably. I then made a new head out of brass, but in my hurry to get making chips, I didn't think it through and didn't leave enough meat on the head to attach the intake and exhaust valve assemblies. So, I made yet another head out of aluminum. Here are the results.

More work done on the top. The threaded hole coming in from the side will be the exhaust side.

Another shot of the bottom after drilling some holes and shaping the sides. The side with the long flat section will be the intake manifold side.

And the top...

Had to bore out the hole in the base to accommodate the larger circular portion on the bottom of the head.

Here's the base with the head bolted in place. I also had done a bit more shaping after I took the pictures above. There is now a raised ring, 1/16" thick and 1/16" high that encircles the cylinder.

And a picture of the base and head with the cylinder sitting in place.

I also plan to fancy up the cylinder, do some kind of curvy profiling on it, but haven't decided on a design yet.
Chuck