Exh manifolds in an Early A...

If you look at the ports, X heads are big. You have to port the X heads to match the exhaust gasket openings. As the years went on, the ports shrunk on 360 and 318 heads. The exhaust ports are not big on magnums. I ported my original exhaust manifolds on the 64 Barracuda to seal J heads. You probably wouldn't have to port the early exhaust manifolds for Magnum exhaust ports. Don't make me take pictures...