Your Mach 1 has the 2.8L, right? If so, I think that the answer is yes. You may need to use the Granada bellhousing, and you may need to change the location of the shifter forwards or rearwards a bit and you may need to have your drive shaft modified, but most machine shops should be able to handle that.
For the 2.3L 4 cylinder, your best bet would be a (Ford) T-5 as it bolts right to the 2.3L bellhousing. The shifter will be about 2 inches farther forward though. The version of the XR4Ti that we got here in the States was only available with a 2.3L Turbo EFI engine and a 5-speed other than the T-5, but it had a smaller torque capacity, so most XR4Ti guys here swap for the T-5.
Good luck, and keep us informed on your project.
78CobraII