Sonny shaved the rocker fins, making the engine look like it's running early cylinder heads, but as the article states it's using later 9-bolt heads and Webcor big bore cylinders. There are later pictures of the top of the engine where you can see the 9th bolt.
The article says that the clutch is stock besides aftermarket plates, but that is not true. It also has a six spring alloy pressure plate made by Routt's Cycle. These were made in a few different configurations including an eight hole version.