6- 10mm x 32mm bolts
6- 10mm x lock nuts
12- 10mm washers
3- 2 1/4" compression gaskets

I searched, and found these result for the size of the bolts. What I do not understand is the grade level. People said just pick up 6 "grade 8" 10mm x 30mm or 40mm Bolts and that will do it. However "grade 8" do not exist in Metric. Next is the pitch size, the cashier said the one I got which is M10-1.50 x 30mm with Class 10.9 is probably not the ideal bolt for header.

I just need confirmation on these:

1. Class 10.9 in Standard Unit = Grade 8 in Metric?

2. Our car uses 1.25 pitch?

3. Where did you guys find your bolts/nut? I went to Kragen, Autozone, and pepboys, and they do not seem to have the perfect bolts.

Thanks

 

Have you tried Napa? They usually have a good selection of bolts.

 

i just bought 140+ dollars of bolts, nuts, and gaskets getting ready to do my header install. whatever i dont use, i get to return back to the dealership. im just concered about halfway though the install and a bolt breaks or has to be sawed off. I just use them as back-ups. the only thing i dont have are the cat bolts and i think thats another 15 bucks. if your ever in doubt or cant find something, your local "i suggest honda" dealership should have the parts in stock. nothing beats a 3 dollar bolt wrapped in honda packaging

 

Went to Honda dealer the other day. I found that the bolts connecting the exhaust manifold to the downpipes are double threaded. Now I am getting more and more confuse. I asked them for the bolts from the downpipe to the Cat, which according to that dude is 10mm x unknown (computer didnt show). More over, they ran out of it.

Found some ideal bolts at another autozone, but do not have 6, they only have 2.

These bolts are 10mm - 1.25 x 30mm with Class 10.9

New question, how the hell do you take off those double threaded bolts? I do recall seeing some hex nut or bolt head from the bottom of the car.

 

they are supposed to be double threaded with one nut per bolt. just buy them. once you do the install, you'll know.
are you doing it for a aftermarket performance header or just something with the stock exhaust manifold because you may need difference size bolts.

yea, the bolts attaching the cat and the downpipe are special order for me also. I just reused the old ones

 

I bought the correct (close enough) metric equivilant in the imperial system - cant remember what it was off hand, but i found them at home depot.