Hybrid bolt in 99 5L head?

[wpurple]

I am stumped.
I had found that my supercharger had a bit of a vibration so I checked the mounting and found one of the bolts for the bracket that mounts to the front of the head a wee bit loose. When I went to tighten it it got to snug then loosened up a bit like the threads were stripped.
Looked at the threads and the bolt and everything was fine. Tried again, same thing. The bolt is a 3/8 16TPI, a 7/16 is too big, so then I tried a 10MM and although it seems that is what I need (It was just a little bigger) the threads were wrong.
Called Ford and they couldn't tell me the type of bolt from their database.

Does anyone have a clue? Seems I would need a 10mm with american thread type.....doesn't make sense but I know Ford uses some funky bolts here and there.

 

[pickupman]

10mm might be what you need, but you have to know what pitch you need for the threads.... I know there's 1.5 and 1.25 pitch (similar to fine thread vs. coarse threads in the american system), and am not sure if there's others.

 

[CDW6212R]

Metric bolts have just as many different thread pitches as SAE bolts. Ford started to go back to SAE bolts several years ago. Now we have to go through the change again. They should have completely switched to the metric system, and never mixed them on the same vehicle.
Sorry we are of little help. Is the bolt one which is also on a stock vehicle. If so, try to get that bolt from a stock vehicle. Good luck,
Don