Which spark plug for #186 casting heads?
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One gear at a time
Joined: Aug 2003
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CI 8-9-10 Veteran
St. Jude Donor '07-'08-'09
Which spark plug for #186 casting heads?
Looking for the correct spark plug for a set of 1970 #186 heads. These heads have the 64CC chamber. I would like a plug in the 45* heat range.
Would the correct plug take a 5/8" socket or a 13/16 socket?
Recommendations would be appreciated. TIA Wes
Would the correct plug take a 5/8" socket or a 13/16 socket?
Recommendations would be appreciated. TIA Wes
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Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by wesmigletz
Dennis, thanks for the reply. Would that plug happen to take a 5/8 or 13/16 socket?
Thread Starter
One gear at a time
Joined: Aug 2003
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Likes: 24
CI 8-9-10 Veteran
St. Jude Donor '07-'08-'09
I just went and tried to install a set of the smaller plugs in one of the heads, and they did not want to seat right. So, I got under the car so I could see the spark plug seat. The seat was flat like a 461 head would have. I pulled a valve cover, and the date looked like C 9 0.
Any thoughts on this?
Any thoughts on this?
Race Director
Joined: Sep 2004
Posts: 11,874
Likes: 263
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Originally Posted by wesmigletz
I just went and tried to install a set of the smaller plugs in one of the heads, and they did not want to seat right. So, I got under the car so I could see the spark plug seat. The seat was flat like a 461 head would have. I pulled a valve cover, and the date looked like C 9 0.
Any thoughts on this?
Any thoughts on this?
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Thread Starter
One gear at a time
Joined: Aug 2003
Posts: 5,228
Likes: 24
CI 8-9-10 Veteran
St. Jude Donor '07-'08-'09
bobs77vette, the 186 head has two small humps and accessory bolt holes, it is later than the "feulie" heads. The area where the plug goes looks like a large, flat circle. I didn't crank down on the plugs, and the threads look fine, so I don't think I damaged them.
I went and pulled a plug on my truck this morning; the truck uses the smaller 5/8 socket plugs. The area under the plug looked different, it was tapered where as, the #186 head was flat.
Dennis, I'm going to pick up a set of the larger plugs on my way home from work tonight. It's been a while since I ran these heads, and for some reason, I couldn't remember what plugs I used to run in them.
Thanks again for all the help. Wes
I went and pulled a plug on my truck this morning; the truck uses the smaller 5/8 socket plugs. The area under the plug looked different, it was tapered where as, the #186 head was flat.
Dennis, I'm going to pick up a set of the larger plugs on my way home from work tonight. It's been a while since I ran these heads, and for some reason, I couldn't remember what plugs I used to run in them.
Thanks again for all the help. Wes
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Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
sounds like there are different sizes ...try dennis's answer if my didn't work....
edit just reread your initial post and i believe those are the heads i have with the small tapered plugs, although i don't know what car they came off of originally? not sure why the difference but sounds like Dennis may have you answer
edit just reread your initial post and i believe those are the heads i have with the small tapered plugs, although i don't know what car they came off of originally? not sure why the difference but sounds like Dennis may have you answer
Last edited by bobs77vet; May 10, 2006 at 04:52 PM.
