Big block engine compartment questions

[vegiguy]

When did Mopar start using valve covers with the built in spark plug wire retainers on big block B bodies? I've seen them on '74's - was this the first year for them? I have a '73 400 RR and want to restore it to original so I need to know which type of valve covers to get. Any pictures of how the spark plug wires were run on these cars in 1973 would be greatly appreciated.

 

[69 Runner]

Welcome. I'm sure someone will chime in with an answer. If not, a good place to look would be in 73 sales brochure