Some of the best fitting headers I've ever had on a A body were the old Summit headers bent like Hedmans. They hang low, but as long as you run stock ride height and stock front tire height, you have plenty of ground clearance.
Summit racings 1-5/8 standard looking street header has always been the best fit.
TTI has been the best fitting next tube size up header for my A bodies. In my B & E bodies, Hooker Super Comps at 1-3/4 have always fit the best, period! They are not that standard header shape.