Cain and Redline Manifold

[HK1837]

I think you'll find that the later ones were made by Terry Hardiman (Redline) for John Cain because Cain's original castings were atrocious hole riddled cast alloy and as you noted a different style and look.
This second style with Cain on it as actually a Redline casting badged up for John Cain. All Cain's original tunnel rams and manifolds now carry the Redline branding and superior casting.

Other way around. Cainy sold all his moulds to Hardiman when he closed down. He used to make them for Hardiman before that. That Holden manifold was made by John Cain in the 80's and on, the earlier mould I believe was modified into a 4BBL manifold. His early manifolds were made here, cast from old alloy.