Fundemental car question

[I hate Rice]

I am a potential physics major so i know what HP, and torque are and how to calculate HP from torque and what not, what i am primarly concerned with is how compression effects torque and horsepower, and how stroke and bore relate to power. Lets say you have a 4.6 but the cylinders are very narrow and long and vice versa were they are very shallow. How does this effect hp and torque. Also what can you do to change compression. It just for my knowledge cuz their are plenty of mods before any deep engine work on my pony. Thank you.