* 170 cubic inch inline-6: This typically produced around 110-120 horsepower. The exact number could fluctuate slightly based on the carburetor and other minor variations.
* 200 cubic inch inline-6: This was a more powerful option, generally producing around 120-125 horsepower. Again, minor variations existed.
To know the precise horsepower of a *specific* 1968 Mustang 6-cylinder, you'd need to look at the vehicle's original documentation (like the build sheet or owner's manual) or the engine's data plate (if it's still visible).