You can use a Fox booster but not with any clutch linkage that sticks through the original hole in the firewall.  One of the booster studs will be residing in that hole.

The 5.0 booster is dual diaphragm and alot thicker, but smaller diameter.  You CAN fit a tandem master cylinder on it, but if it has a plastic tank, you have to modify the back of the tank (heat and reform using a light bulb for heat) to clear the vacuum fitting on the booster.  You also have to be using a Shelby or other aftermarket export brace, and must remove the stub bracket on the shock tower where the original brace bolted up.  That will give plenty of clearance to get to the master cylinder.

A better solution is the slightly larger diameter 2.3L booster which is single diaphragm and a few inches thinner.  It fits fine and works great.  You must use the MustangSteve PB-2 kit components and modify the pedal and pedal support for it all to work.  My cable clutch kit is guaranteed to fit with the booster, all designed so everything fits together and works right.  If you get one kit from me or someone else, and then a clutch kit from another vendor, it is unlikely they will work properly together.  Due to space limitations, it is a real balancing act getting all that stuff fitted in there, and there is really not any room for deviation from the setup as designed for the retrofit.
Your 67 MC will work with the Fox boosters.

1-1/16" bore is too big and you will not generate enough line pressure.

Cable goes around oil filter than along pan rail to bellhousing.  Used to use a shorter cable and the longer one is much better fit.