milling 440source heads

Thanks Mr Hemi.
Forged flat tops with valve reliefs
Why 0 deck the block?
Can I fix my mistake by milling AL from 84 CC to 68 CC"S?I can do this with 440Source One heads. Enough material and I checked.
I would prefer to not tear a running motor apart.

If disassembly is my only real option then I am going to put my 906 heads back on and
go with a centrigul supercharger