Sorry, I haven't checked back sooner. You guessed it, Mopar Performance aluminum valve covers.
Here's a more complete version of the story. The car belongs to a friend. It's a 76 Roadrunner that's getting a 360 to replace the worn out 318. The car itself is pretty tired, so I'm assuming the subframe bushings are sacked, but nobody's actually looked at them. I haven't seen the car in 2 or 3 years. I got a call the other day asking about smaller brake booster options, and it got me thinking.
If it was my car (which I sold a few months ago), I'd go with aluminum bushings, stock valve covers and manual brakes. But that's just me. My friend is set on the MP valve covers and power brakes...