Header Bolt Thread Pitch for 2017 Gen 2 Coyote

[Alan_C]

In researching online, it looks like the early Gen 1 Coyotes used a fine pitch thread M10x1.25mm stud. Later Gen 1 engines and Gen 2 Coyotes appear to have been changed to a course thread M10x1.5MM stud. Researching on Summit Racing, I purchased the Stage 8 locking fastener kit 8914C for later Coyotes. However, I have seen posts indicating Gen 3 Coyotes have the fine pitch M10x1.25mm studs. I am confused and I guess I will just wait on the header bolts I bought and compare to the thread pitch on one of the studs from my engine.
Is there a mixture of course and fine thread manifold studs out there in production. According to Summit, the fine pitch was only used on early Gen 1 Coyotes, but the comments by some that the Gen 3 uses the fine pitch seems to contradict the fitment info from Stage 8 shown on the Summit website.

[JohnK]

My gen 2 coyote (circa early 2019) is fine pitch M10 x 1.25. I've heard of both being used on gen 2, so the best bet is to check what's on your specific engine.

[Alan_C]

My gen 2 coyote (circa early 2019) is fine pitch M10 x 1.25. I've heard of both being used on gen 2, so the best bet is to check what's on your specific engine.

Interesting comment as the Gen 2 Coyote ceased production after 2017 model year. The 3rd Gen with direct injection started production for the 2018 model year. Sure you don't have a 3rd Gen or a 2nd Gen that sat on the shelf for a while prior to sale. That said, if you have the 2nd Gen then there appears to be a mixture of thread pitches used.

[JohnK]

The Gen 3 coyote was introduced in 2018 but gen 2 coyotes were still available for sale through early 2019 when I bought mine from Mike Forte. At the time I purchased my engine I could have selected either a gen 2 or gen 3 as the gen 3 crate engines had just started shipping but the aftermarket support for the gen 3's wasn't mature yet (no oil pan/pickup from Moroso yet, as one example) and I preferred the aesthetics of the gen 2 so went with that.

[Alan_C]

I spoke with a Ford Performance representative and he confirmed the proper header bolt for the 2nd Gen Coyote is fine 1.25mm pitch, not the 1.5mm course pitch. Grade 8 Fasteners has their fitment info indicating that the fine pitch was only used for early Gen 1 Coyotes, that information is incorrect. I received the State 8 Locking Header Bolt kit 8914C with the 1.5mm pitch per their application info and they are incorrect. So both Ford Performance and my engine show the correct part to be the 8914 part with the 1.25mm thread pitch.
I spoke with Stage 8 Fasteners and they said that Ford Production on the Coyote has used both pitches. I don't know about that but my 2017 Gen 2 Coyote definitely uses the fine pitch.
For those out there looking for header bolts, just pull one of the header studs and check the thread pitch before buying.

[JohnK]

I hope this doesn't come across as antagonistic, but this seems like an awful lot of unnecessary phone calls and confusion over something that could be figured out in a few seconds with a thread checker. IMO, these are something that every builder should have on hand. Just in the last couple of days I've seen multiple questions not just on header bolt sizes but alternator post thread pitch as well as others. I have this and these in my garage, and they get used all the time.

[Alan_C]

Yeah if I had the thread pitch checkers on hand, that would have been an easy solution. Not everyone is going to have specialty tools on hand like those. I am retired, so a couple of phone calls was not a big deal. Although not said directly, one on the things I found frustrating is the incorrect application information Stage 8 includes in their product pages.
Sorry I annoyed you with my posts, hopefully it will help someone else.

[lance corsi]

Commie bolts are frustrating, no?

[Alan_C]

Well it took several weeks for someone at the Ford Performance Techline to respond to my original inquiry. Looking at production drawings for the various generations of the Coyote here is their answer.

I pulled the print on early (11) and late (14) cylinder heads.
This is what I came up with.
1.25 x 10 W714869-S431 from 9/8/2010 to 6/27/2014
1.50 x 10 W713604-S431 from 2/3/2011 to 6/27/2014
1.25 x 10 is the only one I see for 15-23
As you can see it is not cut and dry.
I suggest getting one bolt with either a 1.25 or 1.5 pitch and check both your heads

I confirmed that my 2nd Gen Coyote built in 2017 has the fine 1.25 pitch which is consistent with the info provided. Too bad the application info from Grade 8 was so far off.
Weird that it was the 1st Gen engines that had a mixture of fine and course thread manifold studs.