I've got a square-back on mine with no issues, pretty sure the belt is not factory length though that probably makes a difference.
@340doc I think the issue lies in where the long bolt threads into the end of the cylinder head which the alternator pivots on and the spacer that goes over it. That mounting area sticks out farther on Edelbrocks compared to factory heads which pushes the alternator forward if the spacer isn't modified to move the alternator back again. I'll post a pic of my setup after I get home from work today...