where did the 70s take the horses

Granted, stock 318 cam info is not the easiest research project.

My point was that there was no major cam change that accounted for a major difference in horsepower.

I've owned at least a half a dozen 318 cars, and known intimately several times that.

The only ones that perform in a noticeably different manner are the 92 and up magnums, and the 66 and earlier poly, and in that case only slightly more torque, seat of the pants wise.