That loooooong timing chain always makes me wonder if they are the best way to actuate valves.
I know! I know! my 6.9 engine is designed like this! Why do that when only lower engines revs are required?
Perhaps a better way would be the
'Poor man's DOHC' method, with a shorter chain to directly above the crankshaft, and two shorter ones to each camshaft with a spur gear to drive the adjacent camshaft in the head?
Or, perhaps another approach:
Use computer controlled, pneumatic or hydraulic directly actuated valves valves instead. Each valve can be accurately controlled by the engine management computer.
Do away with all that complicated valve actuation machinery altogether.
Actually, most of the anecdotes I have heard is that the 428 was a more reliable engine than the 427.