Via the same system the OE used and in between the rockershaft stand area is a machined flat for use with Magnum rocker systems. The head will have a OE - LA oil pathway for the shaft system and the Magnum is pushrod oiling.
Doesn’t EQ have 1 head drilled two different ways for each? This has been done before DQ with the MP replacement head designed in this manor. 1 head, two different machining process’s for two heads, and part numbers.
History gents! This has been done 10 years ago.