Spark Plugs/gap

[Mustang5L5]

BTW, it's 0.054", not 0.54". I'd like to see this 1/2" gap on a spark plug

 

[navarro98gt]

So does anybody know what the, "Spark plug reach" means? I'm checking out the Autolight 764 and they specify the Spark plug reach @ .807in but the platnum ones are specified @ .708in. So I went to the Motorcraft website and they dont list the "spark plug reach."

 

[Kilgore Trout]

http://www.strappe.com/plugs.html

 

[Killa]

just bought some autolite copper 764, the hayness manual tell me to gap at 0.052, and some people tell me to gap at 0.054. which on is best ? thanks

 

[Killa]

just bought some autolite copper 764, the hayness manual tell me to gap at 0.052, and some people tell me to gap at 0.054. which on is best ? thanks

BTW why the autolite threat is shorter than other plug ? its still ok to use ? thanks

 

[RandyStinchcomb]

So does anybody know what the, "Spark plug reach" means? I'm checking out the Autolight 764 and they specify the Spark plug reach @ .807in but the platnum ones are specified @ .708in. So I went to the Motorcraft website and they dont list the "spark plug reach."

spark plug reach has to deal wth how deep into the cyl the plug goes, a longer reach can sometimes hit the pistons.
also a longer reach on a P/A car is not a good thing as it moves the spark deeper into the combustion process and that in "theroy" is like advancing the ignition timing and can cause preignition/detonation issues, which will destroy the plug and possibly a piston or 2

stock reach is .679

 

[navarro98gt]

Thanks for the info Randy. I was planning on going with Autolites or NGk but after reading the link that Kilgore posted I think I'll just stay with the Motorcraft plugs. I just wonder why other spark plug manufactures dont use the same reach as the stock plugs?