Why are 318's low HP and torque?

Buildin' on a budget y'all. Other than an 8 3/4 rear end my project is complete in parts. Just a little elbow grease and paint and this motor and trans will be detailed and ready to drop in my dart. Since I have a running slant in my dart right now, I'm not in a real hurry to finish the project. But I would like to get this done in the next two months tops.....I hope ha ha. Always something else right?!