One thing leads to another... mean 318?

figure an .125 over bore equals the same amount of horsepower as an increase of 1"of stroke.

I don't think that's a reasonable comparison. I believe a 1" stroke would far out power an 1/8" over bore. In a 440, for example, you're talking about going from a 3.75 to a 4.75 stroke. That's 557 cubic inches.

By contrast, a .125" over bore on that same 440 is only 465 cubic inches. See the difference?