Exhaust Bolt Size? Help, please.

[jackiert]

Does anyone know the bolt size and length for the bolts that mate the header/exhaust manifold to the mids/high-flows?

I want to replace the bolts with better/stronger bolts and would like to know the size and have replacement bolts in hand before breaking it down.

I have a 5.7 with Gibson shorts and high-flow cats, if it matters. Don't think it does though.

[elcobra44]

I wanna say they're 3/8 by 2.5... Just make sure ya get stainless..

[Hemi31]

8mm x 1.25.....I believe it's a 1.5mm pitch.

[jackiert]

I wanna say they're 3/8 by 2.5... Just make sure ya get stainless..

Thanks. Another mentioned he thought he used 3/8 by 3". Is 3" on the long side? Is 2.5" the stock size to your knowledge?

8mm x 1.25.....I believe it's a 1.5mm pitch.

Is that a header bolt to head size? I'm looking for header to mids...

[elcobra44]

Thanks. Another mentioned he thought he used 3/8 by 3". Is 3" on the long side? Is 2.5" the stock size to your knowledge?

Might be three.. I think the 2.5" were a little easier to get in there.

[Fargo59]

yeah, the header bolts M8x1.25 thread stock bolts are like 60mm. but you want from the header to the cat, right? my JBA's have 3/8 x 3". get some grade 8 bolts (or go back to metric with M10 and 60mm, but grade 10 at least)

[jackiert]

Great. Thanks, all. I'll be leaving for the hardware store in a few minutes and this helped me out a bunch.

[jackiert]

Update: I finished replacing the bolts with stainless bolts and the Nord-Lock washers. The 3" were too long. 3/8 by 2.5" were the correct size. Thanks again.

[Hal'sMag]

Using lock washers on that application reqires nor-locks on both the bolt head and bolt nut end, per nord-lock.

[jackiert]

Using lock washers on that application reqires nor-locks on both the bolt head and bolt nut end, per nord-lock.

...and that's how I did it. I'm hoping that I have the same success as Cam did.

[elcobra44]

The bolts I installed yesterday in a set of JBA's were 2.5" and I thought about ya... Glad you got it worked out!

[jackiert]

Yes, I did. Thanks again. I need to loosen them up a bit and raise the exhaust a little with the old "floor jack with a block of wood" method, then re-tighten. I forgot that step, but immediately was reminded when I let her down from the ramps and she started rattlin' on the cross brace. Oh well.