Spark plug recommendation for carb'd 5.9

Bill Crowell said
FWIW, I wasn't sure whether MileHighDart has a Magnum or a non-Magnum LA 360. They don't take the same plugs, do they, since the non-Magnum was carb'd and the Magnum was FI?

Correct, they are different (14mm on the mags, for one).
Autolite 3923 should do the trick, Mile High.