920 heads - What Cam?
Replacing a stock cam is almost always worth the effort. But you have to define your goals. If you’re just after a little lope and don’t want to do a converter or gear swap, I’d stick a comp xe268 in it. I have one in a 70, (9.2:1 advertised) 318 and it runs good, sounds good and doesn’t feel like it gave up anything down low. Problem is they’re out of stock pretty much everywhere.
Xtreme Energy 224/230 Hydraulic Flat Cam for Chrysler 273-360