Gen 4, 5 and 6 GM heads same plug reach?
06-23-2014, 11:48 AM
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Gen 4, 5 and 6 GM heads same plug reach?
I am running Gen 4 GM rect port heads, need to get some plugs for a boat equipped with Gen 6 or 5, sight unseen. Think they all have the same reach but not certain. Thanks
06-28-2014, 07:22 PM
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Ok I researched this and found that they all take .460 reach, standard or extended tip plugs
ngk R5673-7,8,9 or Ngk R5674-7,8,9
ngk R5673-7,8,9 or Ngk R5674-7,8,9
06-29-2014, 09:26 AM
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Thanks Eddie, 9.8-1 runs up to 5600 fairly similar to mine except for the Gen. His is 560hp. EGT's were high on his (due to crappy marine carb I think) so I was thinking 7's with out the extended tip would be a safe bet
