Well after entirely too long my ST is back on the road, now with new spark plug holes, a head gasket and timing belt! Runs great. I've missed it so!
Volutary mea culpa follows - no additional flaming required.
One screwup I did during reassembly - I forgot to put the buckets and shims back on! Doh! I immediately noticed it didn't sound right during a test fire and stopped. Thought on it for a day and had an "aha!" moment. I opened the valve cover to confirm my mistake, and that additionally the keepers had popped off the #2 exhaust valve... I spotted one keeper laying there, the other was not in sight, and the oil return galley was about 2 inches away...
So, off came the exhaust completely, dropped the oil pan and fished out the keeper. Oil pan was cleanest I'd ever seen. Oh, btw, there are two hidden oil pan bolts either side of the drain hole. Life got in the way and a week later I made a new pan gasket, followed by another week of life before I could get back to it.
Saturday I got the valve keepers back on using an old broken 17mm socket. I used a grinder to open a window in the side of the socket and used it to press down the spring. Before doing that I modified an old spark plug with a pneumatic fitting so I can press air into the cylinder to keep the valve up tight. I used my largest breaker bar as a lever pressing the socket onto the spring.I hooked a c-clamp over the engine mount at the rear of the head and used that as a fulcrum for the breaker bar. Pull on bar, spring goes down, drop keepers onto greased up valve stem, and voila, it's back on.
If you remove the LEFT camshafts make sure you align the LEFT side cams with the pencil thin notch in the FRONT of the cams with the cylinder head. DO NOT look at the large notch at the rear of the cams as a reference point, or you won't be able to hand crank the engine over. AND, on the LEFT SIDE only - you line up those cam shaft marks when the belt driven cam wheel is in line with the little dimple on the wheel, NOT the regular mark used for timing belt removal. (This is assuming the Timing marks are all lined up correctly.) This part caught me out as I misread the service manual initially. Note, I did not start the engine with the cams misaligned - if you do so you will damage valves.
Once I was confident the timing and cams were all aligned, STring started up in about 2 seconds. No leaks, and oil and coolant levels were good after an extended idle. 2.5 hours later the horn, exhaust shields, windshield and plastic body panels are all back on.
Whew! I could definitely do that a lot faster now if I had to - hoping I don't have to anytime soon though! Total cost was about $115 for timing belt, 2 timeserts, head gasket, gasket stock for oil pan. Big thanks to Irish for the service manuals on loan!