A lot of those specs are "supporting" players and have little to do with horse power potential, but a lot to do with longevity and quality. A good spark system is assumed to light it all up.
Focus on the "breathing" aspects to determine ball park horse power numbers. It doesn't make much difference what rods or timing chain or
oil pump, flywheel, bolts, balancer, clutch, etc. etc. etc.
For a basic horse power guesstimate:
It's about the cam, heads, intake, piston design. Piston quench and c.r. for instance, forged or hyper doesn't make much difference here. Valve train, induction (FI, carb, size) and exhaust are the big players to try to nail down specs on.