Part Number for plugs to use on GT40 irons?

[Mustang Yawie]

Can anyone tell what part number to use on iron GT40 heads? installing a vortech soon and want to know what number to use for colder plugs? thanks

 

[Mustang5L5]

Stock plug would be an Autolite 764 or a motorcraft 32C

 

[Mustang Yawie]

How Do i figure what a colder plug would be? thanks

 

[Mike92GT]

If your using Autolite, a lower number is a colder plug. So if your using a 764 , the next coldest would be 763.

 

[millhouse]

Ahh...again, autolite 103's are 1 step colder than stock and fit gt40/gt40p's

Edit:

Depending on what you reference, 764's seem to be the stock plug for the gt40's. That would make the 103's 1 step colder. Corral has a good plug reference, although they list the 103's as 2 step's colder than stock (765's).

Anyways, here is a link....

http://www.corral.net/forums/showthread.php?t=436174

 

[Mustang Yawie]

Thanks, ill save that for future reference