Maybe look into cryogenically treatment
“We’re running a factory stock block that we had cryogenically treated, which made it 30 to 40 percent stronger than factory,”
775 hp 376
376 cid Mopar Engine - Engine Builder Magazine
I think the problem is the lack of 600 + hp examples, so it's a little unknown there Ultimate reliability, need to talk to shop/builders that build them on the regular.