They are all the same, unless someone has fitted an alloy head engine at some point. I know Martin uses an old head as a jig to make the manifolds so sounds like something isn't right your end - do you have a picture of the engine?
No just outlet as it has an ‘ole in it. Fix bad bit, sort out surface rust, new lower door panels. Then think about mods. My view is if it works then don’t fiddle with it. As venture further then upgrades. He’s doing me proud