Old School vs Magnum on 86 Dodge W100

My Duster currently has a 5.9L Magnum short block with Edelbrock heads and RPM intake (LA top end). I pulled the short block out of a junkyard 2000 Dodge Ram 2500 with unknown miles; pulled the heads and the cylinders still had cross-hatching with no ridge whatsoever so I plopped it in the back of my Jeep and took it home. I did nothing to the bottom end besides install new rod bearings. The engine routinely sees 5500 RPM and I've had it past 6000, about 5000 miles on it so far and it basically runs like a new engine.

Just some food for thought. If your son is up for the work it might save the most money to just find another Magnum engine, either from a junkyard or off Craigslist or Facebook Marketplace (IF you can hear it run first or be able to pull the heads and inspect the cylinders before you buy it). My shortblock was $150 from the local pull-and-pay yard if I remember correctly.

EDIT: By the way factory Magnum heads are almost guaranteed to be cracked between the valve seats. Like others said though it's usually not actually a deal-breaker it's just that for most engines 99% of the time cracks=no good so that's probably what your machinist is thinking. I haven't run cracked heads myself yet but if the cracks are small and shallow and I needed to throw something together super cheap...