I read this thread earlier having failed to remove the head by the method described in the manuals. I also read some threads on Norton forums. There were posts telling how it is done ie as per the manual, but I didn't find anyone saying they had actually managed it. So I am posting this as a conclusion, it may help someone one day.
I say "no way!" There just isn't enough clearance to get the longer push rods over the barrel by about 1/4 inch.ajscomboman wrote: ↑Sun Jul 26, 2020 3:54 pm I'm led to believe it is possible but many many others have struggled and said no way! The other alternative is to let the motor drop down between the plates and swing forward allowing the head to be removed. I've never attempted this myself.
Solution, as Rob said, was to drop the engine a little which wasn't as bad as I feared... Removed the three front frame studs and one of the back pair which allowed the engine, plates, box and primary to rotate together down about the remaining rear stud This is as far as it would go before resting on the centre stand spring where it hooks into the engine plate... But it was enough