looks like typical detonation damage.
Given your goal I say do an LS swap or similar.
You're going to drop a crapload of coin on all new edelbrock stuff to update a 60's era engine design. Add in cost rebuild 360 and it's a no brainer.
I get the keep it AMC but a modern drivetrain will be way better in every way.
More hp, better driveability, cheaper widely available parts, increased fuel economy, etc.
88 GW, 67 J3000, 07 Magnum SRT8