340 Max HP Potential with X/J heads?

Dwayne is on moparts, but remember this is how he makes a living. He is a very nice guy and answered all my not so smart questions. In 2014 Using my heads and installing new 2.055/1.625 ferrea valves new springs, guides, tool steel retainers, hardened exhaust seats and full porting was about $3000-$3500 a pair. IIRC, but I could be off a bit. I’m old! :) cast iron has its place, but if I wasn’t required to run it I would have done aluminum head.