Ben, my feeling is that it looks 'pattern'. If not then it has certainly had new mounting strips welded on.
As far as I'm aware, all Norton tanks of this period were numbered. Does yours have a number on the 'pump' side ?...I can see no trace of pump lugs either.
This photo shows a couple of original tanks (earliest on the right with the off-set pressed panels)
Differences that I can see include the proximity of the spark plug dimple to the tunnel and the length / shape of the rear corners.
There is no reason why yours wouldn't work and it's probably less fiddly than using the standard bolts but of course it won't look quite right from underneath. It certainly needs a bit of work to make it 100%
Thanks for the info. There are no numbers stamped on the tank and there is no trace of pump lugs. Think I might have to talk to one of my crafty welder friends to make necessary changes.
Can you tell me if the mounting strip has a nut welded on the back or if it is a threaded hole?
Hi Ben, It's a threaded hole in the plate on the original. 4 studs is not a bad idea as I had to repair a tank that the bolt had been done up tight and made a hole in the tank because the original bolt has a domed nipple on the top of it for some reason. I have noticed that my ES2 has had the same thing happen and it weeps petrol down the bolt.
It may be a repro tank but the bottom of it looks good, or the plates have just been replaced. In fact looking at it again, I can't see why they would make the domed holes under the plates if they were going to put studs on them. I think it's a modification for the reasons I have pointed out.
Thanks for your input Horror! The studs do the job but I like the idea of getting it back to how it was…. and I want a place to put those NOS tank mounting bolts I purchased.