wtf? spark plugs dont fit

[carbed87]

a while after i put my cast iron gt-40's on, i tried to swap out the plugs (the ones that came with the heads were painted over) ehan i did, the plugs out of my stocks straight up wont thread in there too big it looks like ..... WTF


ANY ONE HAVE ANY BRIGHT IDEAS? (sorry, always wanted to say that, but really)

 

[ECU5.0]

what number plug are you using?

 

[txstang84]

i just looked on autozone's website, they said use autolite 764, or motorcraft 434...that sound right guys?

 

[cwdunnet]

the spark plugs out of the stock 5.0 heads(e7te's) and the spark plugs out of case iron gt40's are not the same. i noticed that when i switched to gt40 cast irons. i had the auto-lite plugs in mine with stock e7te's they were 25's..and the gt40 cast iron's had to take 764s in autolite. so if u use the autolites get 764's for your gt40's or if u use different brand just cross ref them.

 

[JB66]

Look under the valve cover and get the casting # off the heads. Did you mean the plug diameter was too large?

 

[carbed87]

thanks alot guys, i knew somethin was up with that

 

[Funanin]

not sure if this will help but my aluminum GT40s take motorcraft plug AGSF-32C