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Old 04-24-2024, 02:33 PM
LET LET is offline
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Join Date: Dec 2023
Posts: 40
Default Spark plug won’t start

I have a 67 GTO head code is YX. I’m finishing up the engine and trying to put new plugs in it. I have AC delco R45S Plugs and for the life of me, I can’t get them to start in the hole, they won’t thread in. The plugs that were in it are champion 17 Y. They thread in OK. What the heck am I doing wrong?