Speedmaster spark plug holes improvement??
These are supposedly copies of Edelbrock LA heads. When I read this thread and started thinking about it, I only had access to Edelbrock Magnum heads. The Magnum style Edelbrock heads do NOT have this spark plug situation.
Last night I dug out my Edelbrock LA heads and checked one of them and found it DOES have this same spark plug situation.
Both styles of the Edelbrock head I tested were with the same RC12YC spark plug, the same number recommended by Edelbrock. So basically this recessed spark plug, as seen from the chamber side, is not something Speedmaster did differently.
Also did a search and found an old thread on this subject on Edelbrock heads.
My LA Edelbrock heads are from around 2003. I wonder if they are still like this, since the Magnum version is not?
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