Why are 318's low HP and torque?

Good thing is 318 cams are pretty wimpy 240ish degree with .400 lift even the smallest performance cam gonna make a big difference but since your engine has low compression you don't want to go to large something under 265 degrees I got a comp cam Xe262H on stock long block with a Eddy performer intake and 600 carb with headers and duals on my 85 5th Ave untill I below my rear end in the magazine write up I got the idea from it made 282HP @ 5000 RPM's.