To follow up on what Chris was saying...Copper gasket + aluminum block = dissimilar metals which can contribute to galvanic corrosion. Honestly, I think that LAN's approach to machining in a slight "step" around each cylinder provides enough additional "crush", making stock head gaskets adequate. A related point is that we're starting to see more HG leakage across the EG33 community now that we're getting more engines in the +190k mile region (mine included  ), so I believe we can take it as a given that the stock HGs are good for at least 150k miles (okay, now folks can chime in on how their HGs blew in less than 150k miles  )
-Bill
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Retired NASA Rocket Scientist
Most famous NASA "Child" - OSIRIS-REx delivered samples from asteroid BENNU to Earth in Sept. 2023
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'92 Fully caged, 5 speed, waiting for its fully built EG33
'92 "Test Mule", 4:44 Auto, JDM 4:44 Rear Diff with Mech LSD, Tuned headers, Full one-off suspension
'92(?) Laguna, 6 spd and other stuff (still at OT's place)
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