2.7L exhaust flange to header bolt size

Today one of the bolts that holds the exhaust tube flange onto the header somehow came out. I was driving around and I noticed that it sounded like it had an exhaust leak all of the sudden.
When I got home, I let it cool down and then started it back up while feeling around the exhaust side of the engine to see if I could feel any exhaust escaping from the system. Sure enough, I felt a decent amount of exhaust coming out from between the exit of the exhaust header and the flange that connects it to the rest of the exhaust tubing.
Does anybody know what size and thread pitch the bolt is that holds the two together?
Is there any particular type of bolt I should get that would be better than the other? (ie. grade 8 stainless vs zinc vs galvanized, etc)
If I can't determine the size beforehand, I might see if a buddy can drive me to a hardware store so that I can take the other one with me and use that as a reference.

 

I would check with the local Toyota dealer first

 

If I had to guess size then 10 x 1.25 with 14mm heads

 

Don’t you also need the spring as well or did that stay in there?

 

I'll give them a call tomorrow and see what they have to say and what the cost is through them. I just hope I don't have to wait a couple weeks to get it. I have had to in the past when I got parts via this particular dealership.

Now that I think of it, I don't think there was ever one in there to begin with. I'll ask about that when I get a hold of the stealership tomorrow.

 

After consulting the FSM, it doesn't seem like there is in fact a spring in the assembly.

I also realized that the exhaust manifold has studs on it that those nuts in the diagram thread onto.
Sooooo I guess that the stud seems to have unscrewed itself from the manifold rather than a bolt.....

I am going to see if the dealership is able to get a replacement stud, and if not I guess I will have to use a bolt and a lot of sealant or something to get the job done.

 

You’re probably right, I was thinking of a 2nd gen. My fault, hopefully they can just replace that stud no problem

 

My dealer keeps those studs in stock as well as a Stainless lock nut .

The studs have a male Torx head making them easy to install

I keep 10 or so of each myself

Hardware is M10x1.25

You might want to lock tite the stud to keep it from vibrating out from thermal cycling