Thanks guys,
I’ve attached a couple of photos of my valves and springs to my post. I think based on your comments John, that these are not from an alloy head. But would be pleased if you could confirm. There are no numbers on the valves.
The extent of the rebuild has been nut and bolt. I had the crank reground for an oversize bush rather than an SRM needle roller - due to anticipated lower mileage. Otherwise new bearings seals etc - wheels rebuilt, electrics, new Exhausts fasteners etc etc. Done as much as I could in stainless. Hate chrome - find it heartbreaking when rust comes through.
Musky, I’m confident it is not the guides causing the smoke. Just before I stopped using it , all those years ago, I replaced the original bronze guides with new cast iron ones. Did it with my old man, head in the oven, guides in freezer. Vivid memories of hot and cold burns and colourful language. Also confirmed by my recent, Uber careful measurements. Only one valve stem is on the verge of being undersize. The bores and piston tops are wet with oil. So I think a hone and new rings will sort it.
NB the bores are perfect, not stepped, only glazed. I didn’t replace the rings during the rebuild, used the old ones. Gapped ok. I think that was my mistake.
Another thing, possible contributor, and worthy of note is my recent fitting of an external oil filter in the toolbox. I’m getting an excellent return flow to the oil tank, but wonder if I’m also getting the same / too much to the rockers. Is this possible. Should I choke the flow through the rocker feed with a clip?. Is this common?. ( if the hone and new rings doesn’t sort it).
Anyway back to the valve springs. I’m thinking I need to fit standard A10 GF springs provided the cups, collets are the same. Are the snaps good enough for you to tell?
Any thanks to you both meantime.
Ps Will try to write an introduction shortly.