Long time, no write. I wanted to follow-up on this thread to let everyone know what happened. There's a happy ending.
The delay was caused by my being out of town combined with having no help getting the bike to a shop. After a few starts and stops, that was sorted out and I took my bike to the closet Enfield shop, Heindl Engineering.
We thought the main issue was the sprag clutch, which would need to be replaced or removed. After digging into the bike, they found that a pushrod was loose. Luckily, it didn't bend or damage anything. I asked them to give the bike a once over, which was good, since they found other issues. Example: The noise at the cylinder head? There was no exhaust seal. The original owner must have had a different exhaust and forgot the seal when switching back to stock.
Props to Heindl Engineering. I got my bike back from the shop Wednesday afternoon. This is the first time I've used a shop and I was nervous. The service was quick and Dave and company went above and beyond. They answered all my questions and took the time to show me a few things.
My bike is now running smooth. It's almost like a different bike. Happy to have her back!
As a fringe benefit, while servicing a bike is no doubt expensive, the bill was less than the price of the part I thought needed to be replaced... and perhaps more importantly, the once over put my mind at ease.
Rob