Has duplex chain which has a simple tensioning method involving slackening a bolt, turning the engine round 1 revolution and then tightening it back up.
Engines go on for many miles. Mine has 140,000, uses about 1 pint oil every 3000 miles. Was talking to someone at National Alfa day and he had over 300,000 miles on his 75 with the original engine.
Requires oil change every 6,000 miles or once a year with a reasonable 10w40 semi synthetic.
The variable valve timing is done with a solenoid and appears totally reliable (unlike the Fiat derived 16v engines)
75 3.0 V6