What Cylinder Heads are on that engine.
Usually the Mopar Big Block Heads don't have an issue with cracking, and
we've Pressure Tested many on our AXE Cylinder Head Pressure Tester.
Big Block Mopars do have a small problem with Head Bolts, after lengthy periods
of time in use they do stretch and/or the threads corrode some.
Just chasing the threads won't do the trick. You may have to 'bite-the-bullet' and
purchase new Cylinder Head Bolts.
And both the Cylinder Head and Block Deck should be re-checked with a Straight-Edge
to make sure of no abnormal warpage.
Important;
If the Cylinder Heads were ported, you should at least have the one on the 'problematic side'
'Pressure Tested' not Magna-Fluxed for cracks.