Belive or not, the way it works on dyno's of engine manufactures is
that a test standard engine is used to calibrate the dyno to it's
output. Typically these engines are re checked for repeatable
dependable performace data frequently under government measurements
quality assurance audits.
Check with MOFOCO in Milwalkee, they sell their VW engines
with dyno time on the rebuilds. Don't mention the word airplane...;-)
Ask for a horsepower and torque plot.
I'd say 53-55 horsepower depending on what parts options are used.