Why are 318's low HP and torque?

i have a great little 67 318 that has not been messed with internally and is a great , sound little motor that will more than get out of its own way. i cruise it around and hot rod it from time to time and it is very respectable. in the meantime , i have another 360 amongst other projects that is getting the treatment on the side, and when the time comes, it will merely plug and play.