Both had weak head flow. Windsor heads were very poor but so were teens. Cool engines yes but both were overall mediocre imo. 318 is a bit bigger so there's going to be a torque edge there.
If we're doing a comparison maybe the 273 vs 289 would make more sense. At least there were performance variant of 273.
Boss 351 is the highest powered HP "small block" of the muscle car era.