EXH. manifold bolt size

JosephVK56 · Oct 25, 2017

just bought a brand new 17' ram 5.7 1500 4x4. i knew about the manifold bolt breaking off issues before the purchase but not much about it.. i want to replace all the bolts with new grade 8 hardware before i have any issues (maybe ARP stainless bolts) but what are the exact size i need? im just sticking with the OEM manifolds for a quite a while.

how is the access to these bolts to replace? fairly easy?

i did headers on a titan i used to own and those were a pain in the ass lol

JosephVK56 · Oct 26, 2017

No one knows??

theviking · Oct 26, 2017

Well, considering Stage 8 makes locking header bolts I'd probably just look at those first, assuming the length is correct for a cast manifold. From their site:

These locking header bolts fit the Dodge 5.7, 6.1, & 6.4L Hemi. They measure 8mm-1.25 x 25mm and come with 12 in a package. Stage 8 Locking Header Bolts easy to use but they are absolute insurance against horsepower loss or gasket failure created by loose nuts or bolts.

big13 · Oct 26, 2017

I would hold off. By the time the bolts start breaking, you will want to be up grading to headers. It is a natural progression.

JosephVK56 · Oct 28, 2017

well for anyone curious i confirmed the size - is it M8x1.25 and 45mm long. i got a set of metric 10.9 grade - equivalent of grade 8 SAE. replaced them all in only 1.5hours. the clearance for the manifolds is AMAZING especially compared to my titan i used to have lol headers in titan took me almost 2 days and i could have done shorties in this ram in only like 3 hours at most.

i used the copper high temp anti-seize on all the bolts so at least when it comes time to do some headers i know they will all come out ice and 'easy'

guyc66 · Mar 20, 2018

JosephVK56 said:
well for anyone curious i confirmed the size - is it M8x1.25 and 45mm long. i got a set of metric 10.9 grade - equivalent of grade 8 SAE. replaced them all in only 1.5hours. the clearance for the manifolds is AMAZING especially compared to my titan i used to have lol headers in titan took me almost 2 days and i could have done shorties in this ram in only like 3 hours at most.

i used the copper high temp anti-seize on all the bolts so at least when it comes time to do some headers i know they will all come out ice and 'easy'

Did you purchase those manifold bolts online or local? Please share the vendor info if online....I'm trying to find a good source for these. Thanks!

Bldrinker · Mar 21, 2018

Bolts for manifolds and headers would be different lengths.

I wonder if installing new manifolds can fix the problem.
Not everyone has this issue, it’s almost like if you get manifolds that are more likely to warp than others you get a leak.

Basically luck of the draw on the manifolds you get?

michaelrc51 · Mar 21, 2018

yeah, 8mm x 1.25 x 45mm long for OEM manifolds or 25mm long for headers.

McMaster Carr has a variety.

Bldrinker · Mar 21, 2018

Are you guys using lock washers or flat washers or both?

CanadianNick · Mar 21, 2018

Bldrinker said:
Are you guys using lock washers or flat washers or both?

Neither, flanged bolts for the manifold and flanged nuts to hold the heat shield in place

icetraxx · Mar 22, 2018

When you changed them out, did you just change one at a time or pull everything and change the gaskets and install new the new bolts. I am tempted to replace the bolts but really do not want to get into changing the gasket if I don't have to. this is on a 17 with 20k miles.

JosephVK56 said:
well for anyone curious i confirmed the size - is it M8x1.25 and 45mm long. i got a set of metric 10.9 grade - equivalent of grade 8 SAE. replaced them all in only 1.5hours. the clearance for the manifolds is AMAZING especially compared to my titan i used to have lol headers in titan took me almost 2 days and i could have done shorties in this ram in only like 3 hours at most.

i used the copper high temp anti-seize on all the bolts so at least when it comes time to do some headers i know they will all come out ice and 'easy'

michaelrc51 · Apr 11, 2018

Change the gasket. You’re asking for problems if you don’t. It really doesn’t matter that it’s a newer truck with low miles.

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EXH. manifold bolt size

JosephVK56

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Bldrinker

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