I got to meet Denis back in the late 70's while filming a story on the Portland Air National Guard. Dennis worked as a mechanic for them. He showed me a big stack of photos he had taken while building the Special. He even had several of him flying formation with the Air Guard's T-33's at 25,000 ft.!!! It originally had a TSIO-360.
I knew he had been in poor health lately. Sad to hear about his passing. He was a true inovator and a master builder.