IMO ... 
The plugs are too cold for street. For instance, the FORD AUTOLITE BF-82 was intended for the six and FYB. The BF-42 for the FE. The last two numerical characters give the heat code for the plug.
The BF-32 was used for HIPO street, but it was used with high compression and IGN LEAD
So you see the extreme. They will cold carbon foul.