This is a new, made in England, genuine part from the old Triumph factory at Meriden. The casting number is 71 2863 HDA  and I believe the part number to be 71 2807.  A very late 650cc 9 stud head to take the rocker boxes with dowel pins. It comes with a set of new bronze valve guides, has stubs for push-over exhaust pipes and the bolt-on carb manifolds that were used on late 1972 T120s ( and into the 1973/4 right-hand gear change T140s and on to the lefthand change models up to 1978).  

The factory would have fitted the exhaust stubs and manifolds onto a bare head. There is no way of knowing when they put them together but the factory was permanently short of funds and always keen to make the most of the stock that they had whilst also keeping bikes on the road. So, with no spare funds to get extra parts made, everything being focused on producing the bikes, that will be why they have had to use two same-handed manifolds - presumably having no spare pairs in stock.

I can't give you full details of a rebuild but if you are wanting to fit this head to an earlier T120, there are a couple of things to take into account. Firstly, of course, it takes the rocker boxes with locating dowels which were fitted from 

about 1969/70 on. The rockerbox gasket for the earlier unit models sits nicely on this head so, presumably, the rockerboxes will too. BUT, although the tappet guide blocks from 1969 to 72 are the same, the pushrod tubes are different.  As too are the head and rockerbox bolts. The 1971/2 oil-in-the-frame T120s did away with the long through stud that the torque stays attached to, in favour of a two-piece system that meant you could remove the rockerboxes without having to disturb the head.  I don't know how this will affect trying to put earlier rockerboxes onto this late head.    Ultimately you may need to check things out with your local dealer who will be able to advise you and supply the parts you need to change. 

  

Unless, of course, you have a 1972 T120 in which case --- what are you waiting for?

This part is about 50 years old and although it has spent most of that time in the corrugated cardboard it arrived in, it has managed to pick up a slight scratch to a rockerbox surface and a light bruise to the alloy on the head gasket surface (see the top righthand corner of the last photo).  I have reflected these slight blemishes and the unpaired manifolds, in the price.

Please make sure you wash it off thoroughly before fitting as the surfaces are not clear of machining dust.