Why are 318's low HP and torque?

I tell you what, I have a stock bottom end 318..I added an Edelbrock Performer RPM cam and lifters, the RPM manifold, a set of RHS heads prepped by Brian @ IMM, 1.5 Hughes roller rockers, a MP windage tray and viscous fan package, and a 650 holley spread bore carburator. FBO ignition equipped as well. This "little" 318 has some power! It pulls and pulls, and revvs to the moon! 6500 RPM's -No Problem! It's in a 68 cuda fastback with a 3.55 sure grip rear, and 24.5" diameter tires. It definitely rips for what it is! I am very impressed with this little engine. Spins the tires with ease, and gets sideways like no ones business. Chirps 2nd gear in my TransGo 2 shifted 904 with a 3000 stall, and will get squirelly too!

Specs of heads: 202/160 stainless valves with 5/16 stems, beehive springs.
Cam: 234/244 Dur @ .050" 488/510 lift 112* lobe sep. 107* centerline

Currently I am probably at 8.7 - 8.8 to 1 compression. Is there more in it? Absolutely! Bump it up to 9.5 to 1, add a custom ground solid roller, fully port the heads, and hang on!!