Hi Guys
Those manifolds look just like a set that was fitted to a Beetle I bought in the late '70s.
It was supposedly fitted with an Engine built by Autocavan a few years earlier? Perhaps Keith can shed some light on that possibilty?
But that said it could have been a 'Bitsa'.. I've never seen Manifolds like those since in UK.
I do remember thought that they were not great manifolds and the Aluminum was a bit Cheesy.