Re: Spark Plug Thumb Nuts Thread Size Home › Forum › Ask A Member › Spark Plug Thumb Nuts Thread Size › Re: Spark Plug Thumb Nuts Thread Size wagemakerReplies: 64Topics: 14 February 21, 2018 at 8:44 pm #71428 These should work. Less than the price of a tap and drill. https://www.ebay.com/itm/one-PAIR-of-Vi … 9006!US!-1