I've ordered everything to do long tubes and dual exhaust for my 06 fx4. But the one thing I can not seem to locate is the correct size header bolt. Some sources are stating an 8mm bolt, while others are stating 10mm. KMAC seems to think his are 8mm(yeah I'm throwing you out there). Does anyone for sure know? I have checked tasca, summit, jegs. Damn. If I wasn't heading out of town for the weekend if phone the Ford dealer tomorrow. Thanks in advance.

 

I just did mine a few weeks ago. The manifold studs are 8mm x 1.25mm thread pitch.

 

Thank you! I'll have to order them asap.