my buddy is needing some help with plug gap with a set of gt40 heads
 

my buddy has got a problem he has a 302 with a cobra intake b303 and a set of cast iron heads and he was is needing help on what would be the best plugs for them and what to gap them at thanks for ur help

Get the plugs that Ford Motorsport recommends for those heads. Gap them at .045".

For more or less stock GT-40 setup, the Motorcraft AWSF32C is the stock plug. Gap is recommended at 0.050" to 0.054" if I recall. He could also run and Autolite 104 or 764 plug in those heads.

If he's going serious with the setup (compression, aftermarket ignition, etc.) then he might try one heat range colder in the AWSF22C or Autolite 103 and try gapping the plugs down to about 0.045". I wouldn't do that though at the stock compression.

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Jeff Chambers
Trophy Stock #3
11.462 Seconds / 117.43 MPH
Chambers Racing Team