I run stamped mopar rockers that are 34years old, about 130,000miles on them, i daily drive it HARD, and go to the track about monthly with no issues. There is nothing wrong with them if you ask me. Friend of mine runs a similar setup with no issues. Mopar overengineered a lot of their parts, they are built not to break...there is nothing wrong with your rockers, unless your running some kind of crazy spring pressures (which you shouldn't be). Mopars rocker shafts were so far superior to what the competition was running from the factory. I'll use them on any mild motor i ever build. Have you properly checked your lifter pre-load?
o/t - You have the carb that will feed a 4bbl slant six, not a cammed, alum intake, worked exhaust 318. I run 650cfm on my 318. You should be around 600cfm, not 450, way under-carbed if you ask me.
Just my two cents. Oh and I've heard good about Crane golds, but overkill and unecessary for your setup if you ask me. I'll be running them on my ~400rwhp roller 360 :salute: