whilst having a clear out in the garage i came accross a set of these, they are on a cast manifold, and they are pretty clean really, i will have a quick look inside them tomorrow and see how they look.
i have no idea where i got them, i was pretty sure i sold them ages ago!
i have had a look on ebay but the prices are very varried, what you 'orrible lot thing they are worth and i'll try them on here before going on fleabay.