The Aston Martin Valkyrie AMR Pro is very similar to the McLaren Senna GTR both in terms of its intended use and the state of development. Aston won't begin deliveries of the AMR Pro until 2020, and development will continue until closer to launch, including input from Red Bull Racing. 

Aston Martin promises that the AMR Pro has "over" 1,100-horsepower from its hybrid-assisted V12. Since the company already has buyers for all of them, we can safely guess that the production model packs at least that much output.