I agree that the early Cain manifolds were troublesome. They were from memory old pistons recycled. I remember buying some red 6cyl manifolds with holes welded up. Still worked fine and were less than half price. I don't think John cast the later ones, they were possibly done for him, but I don't believe it was Redline who did it, Cainy organised the work for both. I also think it was only some manifolds involved, as Redline had their own range as well.