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Anyone know where to find these deep thicker plugs for the Olds head? Thanks to Andy for the pic.
Also can someone confirm that these are 1 1/4" for the big blocks.
Last edited by tru-blue 442; Oct 26, 2025 at 11:14 AM.
Dorman 565-023 is 0.4" deep; 565-024 is 0.26" deep. The hole is 1-1/4" and can be tapped for 1" NPT plug if the end of the tap is cut off so it does not have to go so deep into the head (if you prefer pipe plugs over cup plugs).
