YES 5.9 Magnum manifolds work in early A bodies. Here is exactly how!

Tad said
Passenger side is very close especially since I shimmed up the driver side. There’s probably in one section about an eighth of an inch between the inner fender and the embossed numbers on the manifold. Driver side has plenty of clearance

You can grind those number off ...as well as a little casting roughness for extra clearance!!