My engine started to smoke heavy and idle became erratic. I stripped the engine hoping to change the rings but found scored bores. I suspect the engine ran lean prior to mapping and caused this. The engine never overheated once and it was alway driven gently untill the oil got up to running temp before being driven hard.
The cam has done the same mileage as the head mate.
I would have to weigh the head but I think a courier would be no more than £10

Grant