Reading Spark Plugs

toolmanmike said

What number are those plugs? They should be a RJ12YC. Those look like small block plugs. (LONG REACH)

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That's the correct plug TMM. In his OP he said aluminum heads. If that is correct it should take the long reach plug. He could run the N plug but it has the 13/16 hex. The C is the 5/8 and is much easier to use in almost any application.