The new F1 turbo formula is not about maximum engine output. It's about high engine efficiency and energy recovery.
They have the rules written so that the engine output is limited to ~550-600 HP, and another 210 HP available from Kinetic and Thermal Energy Recovery systems.
The engine output is limited by a fuel flow limit of 100 kg/hr, and an onboard fuel capacity limit of 100 kg of fuel to complete a 300 km race.
So with a fairly typical high-performance engine tuning running 10% rich for best power, this racing engine would require 9.8 psi of boost pressure at 15000 rpm to reach the 220 lb/hour fuel flow limit. Assuming a 35% thermal efficiency, the engine would make 557 HP.
If the engine were tuned to stoichiometric air-fuel ratio, and downspeeded to 12000 rpm, it would require 19.8 psi boost to reach the 220 lb/hr fuel flow. Because of the lower crankshaft speed, which reduces friction, and the chemically correct air-fuel ratio, the engine could be expected to have ~10% higher thermal efficiency, so peg it at 38.5%. This would allow the power to increase to 613 HP.
I have recently read that F1 engine constructors are planning to actually run the engines lean of stoichiometric by as much as 20%. Maybe they can do this with direct cylinder fuel injection. Also, the new rules specify that the 100 kg/hr fuel flow limit applies down to 10500 rpm, and below that, the allowable fuel flow is decreased. Downspeeding again to 10500 rpm, leaning the air-fuel ratio to 17.6:1, and boosting the thermal efficiency to 42% gives a required boost pressure of 33.1 psi and a power output of 668 HP. (This last step I don't believe is feasible, as good diesel engines in heavy duty trucks run at thermal efficiencies of 42%, not racing engines running at 5 times the crankshaft speed and lower compression ratios.) But anyway, these 3 "tunings" bracket where I think the new F1 engines will be operating.