This article has further details:
To keep the reciprocating weight as low as possible, which enables this engine to scream to 10,400 rpm, the forged Wiseco pistons weigh just 260 grams and are supported by a set of 340 gram aluminum GRP “Pro Stock” connecting rods — producing some serious cylinder pressure with a 16:1 compression ratio.
- the engine can rev up to 10,400 RPM
- compression ratio is 16:1
Assuming 16 bar effective working pressure, I get 502 hp with these updated numbers:
Effective power = engine displacement
× effective working pressure
× engine speed
= ( 2.7 / 1000 ) m^3
× ( 16 × 1e5 ) Pa
× ( 10,400 / 60 ) 1/s
= 374,400 W
= 502 hp
For regular unleaded octane, a 16:1 compression ratio is usually a recipe for auto-ignition/detonation. It seems that the reason this engine can afford such a high CR is because it is intended to be used with detonation-resistant race fuel. From the same article:
And a 70/71.5 mm Kinsler induction system pulls air in through a set of CNC ITBs before injecting the required Q16, Methanol or similar race gas.