So I was going to take my plenum off to give it a clean and everything else in and around there a good clean also.. but as I was undoing the hex screws on the plenum, one of them just started to strip and did not budge, now it is stuck and I cannot unscrew it..

What do? :\

Try harder...

If it is indeed seized... Like stainless on stainless does... You have a few options... If the bolt is mild steel you can drill it and tap a three in there... Or dill it oversize and put a helicoil in it... If the bolt is stainless you'll have to buy a bit for drilling stainless and go real slow and keep it cool or you'll surface harden the stainless... This would be probably a drill it oversized and helicoil it type scenario... Or you can go buy a new upper or lower BBM assembly or a wreckers or mate...

Cheers,
Tim

Ford from factory apply a loctite thead sealer to the top half of the BBM allen key bolt threads, you were better of removing the complete manifold and spraying it out with carbi clean....

Yea I noticed that when I was taking the first bolts out, but they all came out fine but just that 1 bolt... I'm leaving it for now and I'll probably end up buying another whole BBM, as I wanted to eventually polish it. But that takes a long time and I need to use my car almost daily.

Thanks for the help anyway