[motomiata]

This sounds exactly as my 72TMFI engine. The sound in my engine appeared after the third start up after 4 years sitting during the restoration of the rest of the car.

It's clearly a high pitch metal-against-metal sound, intermittent, non rytmic, and only at idle. I didn't had the nerves to keep the engine running for further investigation, but has started dismantling in order to check the timing chains and the valve train components. The only work on the engine during the 4 years has been upgrading the chain tensioners to Carrera type, setting the valve lash and retiming the cam shafts.

I will post any progress.