Occasionally you will have an M-25 with longer manifold studs as it shipped from the factory. Unfortunately this engine was not one of them. In order to install the new alternator bracket it utilizes the manifold studs to hold the new bracket to the engine. If these studs are too short as they are here, they need to be replaced.
NOTE: If you have any room at all to get a second nut on the stud they can be pulled without removing the manifold! Unfortunately, as can be seen, this engine had zero clearance beyond the nut necessitating removing the entire manifold to do this job. Not all engines came with studs this short. If your are long enough to get two nuts on USE THAT METHOD.....