!!! - Specs circa April 2004, so cam and compression ratio do *not* match the QAC as-delivered engines - !!!

Found on archive.org:

https://web.archive.org/web/20030422080238/http://www.revmasteraviation.com:80/products/r2100_engine/r_2100_curve_spec_sheet.htm

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R-2100 SPECIFICATIONS

Model R-2100, aircraft engine, wet sump
Dry Weight - 165 lbs
Bore: 92mm
Stroke: 78mm
Compression Ratio: 8:1
Camshaft lift @ valve: .394, Duration 274 degrees
Ignition: Dual CDI, Advance 25 degrees max
Spark Plugs: Bosch platinum 14mm (8)
Carburetion: Single RevFlow 34mm
Fuel: 100LL
Oil: 20/50
Exhaust: four into one
BSFC: .49 lbs/hp hour