They can be swapped, but there are a few differences.

Most Alcohol heads use special head studs that allow the removal of the rocker gear without affecting head torque. It's a special stud with two nuts. The head must be cast and machined for this.

Fuel heads also run rocker arms with no roller tips (at least on the exhaust). The valve sizes are a little different too because it has more effect with an alcohol motor. The CR is different, but that's up to the piston not the head.