Why are 318's low HP and torque?

I've been looking for an 8.75 rear end during this whole process with no luck. I always find someone who says it's a complete rear end and then I get there and it's just a housing or just a posi. Furthermore I have front discs, new suspension, and a small block v8 frame already in the car.

I tore the block down to a long block, not too bad. All the accessories, intake manifold, valve covers, oil pan, water pump ect. are off of the engine now. However, I need to do that either way for my original build as well.

My engine is on my stand and I am cleaning it and painting it now. I'll post pics when it's nice and detailed. Thanks for setting me straight guys. Just needed a kick in the pants to keep me going!!!