GT40 heads what plugs?

[Jking8]

1978 f100 with 1994 cobra 5.0 E303 cam GT40 heads what would be the preferred plugs. I know a lot of people are running the autolight 764 but aren't the 104 the same plugs except for the 104 have more threads? There for making it stronger and I've heard they also seal better??? But I would like to try a E3 plug maybe the E3.54???

 

[O'Rattlecan]

Isn't the Motorcraft SP417 the correct plug for that head? I put some heads just like that on my 351w, and I am pretty sure the SP417 was the correct plug.

In my experience I've never had a plug work better than a Motorcraft in a Ford engine.

Ryan