This Engine Simulation or Engine Calculator app will help you model a representation of the airflow going through a particular engine. You can use it to predict horsepower for a given engine combination.
It uses info like the engine bore and stroke, cylinder head CFM and the size of the cylinder head ports to estimate what the engine characteristics will be like meaning what RPM it will make peak torque with a given setup.
You can take it a step further and include a tune using Air fuel ratio, BSFC and boost level (OR VACUUM) to estimate the horsepower the engine will make with that given tune.
It will help you see how your camshaft and cylinder heads line up, and give you an "estimated horsepower range" based on the airflow going into the engine.
It also has cylinder head velocity and an RPM tune to estimate a full RPM range.
Because it's all airflow and a tune, the best way to get started is to work backwards from a known engine combination and some "demo engines" are included based on common specifications for engines. If you know a starting point you can begin to create an engine tune based on new parts.
It has a suggested carburetor CFM, fuel pump flow and fuel injector sizing whether you're working with EFI or Carburetor it's all fuel and air.
You can change part specifications within the app using the various screens for engine bore sizing and cylinder head specifications.
This project slowed down and I just update it from time to time to keep it working on newer phones. I might rebuild it one day because I personally really like the project and had fun learning about engines in the process of making it, I appreciate your download because it shows interest in the project. It is a free app made and maintained by an individual I made it as a personal project because I like cars and engines. I like using the app myself, I hope you do too. Thanks.