I'm in the middle of installing headers on my 2006 5.4 and can't seem to find the correct torque specs for the exhaust manifold bolts. What do I need to torque them down to? I'm using Percy Split-Lock bolts, if that makes a difference. Also, if I can't use my torque wrench on some, how harmful is it to guess?

I also need to buy two O2 bung plugs for the headers. I believe the thread size is 15x1.5 mm (not 100% sure) and I can't seem to find them in that size. Where can I buy some? Again, does it matter if I drive my truck around for a week or so with the exhaust leaking out of the unplugged bungs while I wait on plugs to come in?

Thanks guys!