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Looking for lead on Flathead 6 exhaust manifold long stud (P/N 103203) (3/8" NC x 3/8" NF 3" 3/4" long )


Zakman
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Yep, i was thinking the same thing, but don't think my Harbor Freight set will do the trick. I know, someone must have an old cracked engine block that still has two of them on it.

Hoping someone has one in a barn or in a field and just remove one.

I'll leave this posted for awhile.

Zak

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Dorman part number 675-080 is a 3.75 inch long grade 8 automotive stud, 3/8-24 x 5/8 long thread on one end, 3/8-16 thread on the other.

 

Summit Racing carries these in a 10-pack. $20.89

 

Dorman 675-080 Dorman Double-Ended Studs | Summit Racing

Screenshot (65).jpeg

Edited by Str8-8-Dave (see edit history)
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Dorman and their "HELP" line have helped many a hardware missing/broke problem go away!👍

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On 10/5/2022 at 10:00 AM, Bloo said:

It might help to post what make/model/engine this is for. Good luck on your search.

 

If it doesn't work out, I am pretty sure you can make this from a long bolt with your Harbor Freight tap and die set.

 

34 minutes ago, Peter Gariepy said:

Year/Make/Model might help

Part number in the topic heading is for a Chrysler "plain steel stud" with the thread and dimensions listed in the heading. Pretty sure this is for a 1933-59 Plymouth or Dodge 6 cylinder engine. It might also be for another Chrysler L-6 engine from that period or even for industrial engines into the 1970s.

 

Agree with just getting a long bolt, cutting to length, then threading the cut end with an appropriate die. Quickest, cheapest and easiest way to do this. And you don't need a grade 8 or even grade 5 for this application. A lower grade bolt will be softer and easier to thread with your Harbor Freight tap and die set.

 

15 hours ago, Str8-8-Dave said:

Dorman part number 675-080 is a 3.75 inch long grade 8 automotive stud, 3/8-24 x 5/8 long thread on one end, 3/8-16 thread on the other.

 

Summit Racing carries these in a 10-pack. $20.89

 

Dorman 675-080 Dorman Double-Ended Studs | Summit Racing

 

Good to know that Dorman makes one and that you can buy a 10 pack. But the torque on the exhaust manifold stud nuts is 15 to 20 ft-lbs. You hardly need grade 8 for that.

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21 minutes ago, ply33 said:

 

Part number in the topic heading is for a Chrysler "plain steel stud" with the thread and dimensions listed in the heading. Pretty sure this is for a 1933-59 Plymouth or Dodge 6 cylinder engine. It might also be for another Chrysler L-6 engine from that period or even for industrial engines into the 1970s.

 

Agree with just getting a long bolt, cutting to length, then threading the cut end with an appropriate die. Quickest, cheapest and easiest way to do this. And you don't need a grade 8 or even grade 5 for this application. A lower grade bolt will be softer and easier to thread with your Harbor Freight tap and die set.

 

Good to know that Dorman makes one and that you can buy a 10 pack. But the torque on the exhaust manifold stud nuts is 15 to 20 ft-lbs. You hardly need grade 8 for that.

 

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52 minutes ago, ply33 said:

Part number in the topic heading is for a Chrysler "plain steel stud" with the thread and dimensions listed in the heading. Pretty sure this is for a 1933-59 Plymouth or Dodge 6 cylinder engine. It might also be for another Chrysler L-6 engine from that period or even for industrial engines into the 1970s.

I guessed Chrysler too, but would have had to dig out books buried deep to verify it. I think most people would gloss over the post unless it was something they immediately recognized. Then they might go look in the garden. I know that was my reaction. I am not chastising the original poster in any way, or growling "post the make model and year" or anything like that, just suggesting that the post might be more effective with that information.

 

16 hours ago, Str8-8-Dave said:

Dorman part number 675-080 is a 3.75 inch long grade 8 automotive stud, 3/8-24 x 5/8 long thread on one end, 3/8-16 thread on the other.

 

Summit Racing carries these in a 10-pack. $20.89

This is hands down the way to go. They're grade 8! You definitely want high strength studs to facilitate easier removal in the future. Cutting and threading a bolt as I suggested is most likely going to result in a weaker stud. Low torque or not, studs in this duty always seem to rust up and then break when someone tries to remove them.

 

Edited by Bloo (see edit history)
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Later year MoPar flatheads used bolts instead of studs on those two center exhaust manifold fastener locations.

The reason...made it easier to remove the manifold as the studs rusted and usually broke off.

Also on some vehicles the long studs made it impossibile to remove the manifold as it hit the indentation at the firewall before comete sliding off the two studs.

You ended up cutting the studs off as you had no way to unscrew the studs...tight access.

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