Resolved 1G What is this hole on the intake side of the head

[RLSchwabe]

Can anyone tell me what the hole circled in red is for? Someone filled it with silicone. It's a 91' 6-bolt. I've searched the forums but couldn't come up with an answer. Thank you.

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[Newfie2004]

Can anyone tell me what the hole circled in red is for?

I think it is for the EGR. Not 100% sure, though

 

[fwdmaster]

I think it is for the EGR. Not 100% sure, though

That’s correct.

 

[DSMPT]

EGR port. If you want to block off there, remove that silicone and tap for a 1/8" or 1/4" plug to block off. If you let that port open and block off the EGR valve on the stock intake manifold, use a OEM or aftermarket metal intake manifold gasket. Shouldn't use a paper or thermal intake manifold gasket if you let the port on head side open.
Search with Head EGR Port Block Off. You will find many info.

 

[RLSchwabe]

Thank you so much guys!

Reference: https://www.dsmtuners.com/threads/egr-block-off-plug-size.421180/