I'd guess that in other (Ford) applications, the OEM manifold has a thicker flange plate, so the studs are long enough for this. If the studs were cut down, the removal of the star-profiled end would mean you couldn't easily remove them if a nut became seized.
I meant the bolt in the bottom right of the picture, not the manifold studs. It might be a bit of overkill to shorten the manifold studs.
