Displacement builds torque not HP, if you look at similar NA HP engines of different displacements and even brands the general specs are usually very similar eg. a 550 hp street/strip 302 vs 340 vs 400 M vs 440 vs 454 etc.. they will be in the ballpark of cam size and head flow. Just the powerbands and torque will very greatly depending on size.
A 318 may or may not make the same but it's not gonna be 70 hp difference.
