Why are 318's low HP and torque?

The 1970 factorie hp rateing for the 318 2 barrel dodge was 235 hp and the 1972 340 4 barrel was 245. The 318 had compression the 340 had carb,cam, and a pretty good heads on it. So a 1970 318 with carb,cam,and air sould make closet to the same as hp the 340's

But wasn't 1972 when net HP ratings began? So you're not comparing apples to apples there.