98 F150 4.6l Help

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Ok It’s not a mustang question but I am having a problem with my winter/ bad weather vehicle. As many people know, except me when I bought the truck, that they have exhaust manifold problems. They warp, crack and even have studs that brake off. Well after putting 400 miles on it, mine went and now the warranty people are screwing me around. Long story short...I purchased headers and will put them on if the warranty doesn't cover this but I need a little help on the stage 8 locking bolts. What thread pitch do I need? I keep seeing two different types 3/8-16 1inch and 8mm-1.25x25mm and have no idea what I need. Are the heads on the truck the same type of 2v heads on the mustangs?
BTW With the SS headers and locking bolts I will still be ahead of the game. The dealership wants $1200 to fix it.

[SK@StreetLethal]

The heads are the same as the mustangs. I'm almost 100% certain they are metric.

[Smallville]

I AM 100% certain they are 8 x 1.25. I have fixed MANY rusted/broken manifold studs on these motors.

[Ares]

Yep metric

http://store.summitracing.com/partde...6&autoview=sku

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Thanks for the help guys!!
I hope the stainless steel headers and volant CAI wake this truck up a little. It seems that some of my mustang money is being spent on this truck.

Ares,
That is the part I had sitting in my cart but I was waiting for an ok.