Commando cylinder heads P4876785

In the Mopar parts book for P4876785 *Aluminum Commando Cylinder Head — 2.02" Intake, 1.60" Exhaust it states that modifications are required to the shafts. Does anyone "like BJR" know what mods they are talking about and/ or are there mads to be made to bolt a set of these on with standard LA adjustable valve gear assembly?