FWIW

It's more efficient to skip the puzzle solving and investing money in alternate ways to find a 'potential' crack and take the head to a machine shop - it's the safest and probably the most accurate way to detect any defects with engine components.

Why chance it with the dye that may not be able to detect a crack? Leaving it to the machinist to pressure test/magnaflux and address the issue thereafter. Too labor involved to chance it.

just my humble opinion.