Author Topic: 186 heads  (Read 5530 times)

Jcdubs

  • Newbie
  • *
  • Posts: 5
    • View Profile
186 heads
« on: January 27, 2019, 12:46:53 AM »
I have a set of 3927186 heads I can't find any information on.
 They are date coded E278 and E298
Here is the kicker, thay are angle plug heads.

Jcdubs

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: 186 heads
« Reply #1 on: January 27, 2019, 01:02:40 AM »



firstgenaddict

  • Hero Member
  • *****
  • Posts: 2882
  • caretaker of 1971 LT1's 11130 & 21783
    • View Profile
    • Groome Family Automobiles
Re: 186 heads
« Reply #2 on: January 27, 2019, 03:12:10 AM »
I think you will find that they are plugged and redrilled... I had a set which I got with some parts back in the early 90's.
 186's use the larger flat seat plug with the 13/16 hex.
James
Collectin' Camaro's since "Only Rednecks drove them"
Current caretaker of 1971 LT1's - 11130 and 21783 Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
https://plus.google.com/photos/112392262205377424364/albums?banner=pwa

Emo1956

  • Member
  • ***
  • Posts: 165
    • View Profile
Re: 186 heads
« Reply #3 on: January 27, 2019, 03:54:08 AM »
Ya someone made them that way .

dannystarr

  • Hero Member
  • *****
  • Posts: 1745
    • View Profile
Re: 186 heads
« Reply #4 on: January 27, 2019, 05:40:19 AM »
So that would be May 27th & 29th 1968? Danny

Jcdubs

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: 186 heads
« Reply #5 on: January 27, 2019, 01:24:22 PM »
Can't imagine going through all that and leaving press in studs.
The date is odd to?
I have had these to 25 years, trying to thin out the hoard,lol

Jcdubs

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: 186 heads
« Reply #6 on: January 27, 2019, 01:45:56 PM »
Upon closer inspection you are absolutely right.
They were filled and drilled.
They did a nice job, for what gain who knows.


BillG

  • Member
  • ***
  • Posts: 148
    • View Profile
Re: 186 heads
« Reply #7 on: January 27, 2019, 03:26:21 PM »
Header clearance mabey?
Bill Garrett

z28z11

  • Hero Member
  • *****
  • Posts: 1853
    • View Profile
Re: 186 heads
« Reply #8 on: January 27, 2019, 04:47:42 PM »
If I was really energetic I would look back through my old Hot Rod mags and find the article for the company that made the kits to plug the original plug holes and redrill with the angled small plugs, which mimics the configuration that GM started in the early 70's (better flame pattern during combustion in the chamber). Screw-in inserts and a drill bushing/fixture to drill the holes, wish I could pinpoint the year and look it up. My Hot Rod subscription started in '70, still have them all (like an idiot) up until 2005, give or take a year or so. 

Regards,
Steve
1968 Z28 M21/U17 BRG/W 1967 Chevy ll Nova SS 
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06  1949 3100 5wd 235/6

firstgenaddict

  • Hero Member
  • *****
  • Posts: 2882
  • caretaker of 1971 LT1's 11130 & 21783
    • View Profile
    • Groome Family Automobiles
Re: 186 heads
« Reply #9 on: January 27, 2019, 11:11:29 PM »
Can't imagine going through all that and leaving press in studs.
The date is odd to?
I have had these to 25 years, trying to thin out the hoard,lol

I would have to agree on that...
The pair I had - were 292's - with screw in studs, guide-plates, doublesprings w/dampers - fully ported, and polished D-shaped Exhaust ports- gasket matched on the intakes through the throats and pockets with the chambers smoothed of sharp edges- bronze guides - Teflon seals -  2.05 intake valves, swirl polished with undercut stems, titanium retainers, & 10deg locks.
James
Collectin' Camaro's since "Only Rednecks drove them"
Current caretaker of 1971 LT1's - 11130 and 21783 Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
https://plus.google.com/photos/112392262205377424364/albums?banner=pwa

Emo1956

  • Member
  • ***
  • Posts: 165
    • View Profile
Re: 186 heads
« Reply #10 on: January 28, 2019, 01:04:59 AM »
The angle plug was pointed toward the exhaust valve for better burning of the combustion chamber which made more HP. This is a set of 292 turbo heads that was run in NASCAR and then I ran on my dragster. I still have these heads. They made a lot of HP

69Z28-RS

  • Hero Member
  • *****
  • Posts: 5778
  • owner since 4-Apr-1976
    • View Profile
Re: 186 heads
« Reply #11 on: January 28, 2019, 03:15:09 AM »
If I was really energetic I would look back through my old Hot Rod mags and find the article for the company that made the kits to plug the original plug holes and redrill with the angled small plugs, which mimics the configuration that GM started in the early 70's (better flame pattern during combustion in the chamber). Screw-in inserts and a drill bushing/fixture to drill the holes, wish I could pinpoint the year and look it up. My Hot Rod subscription started in '70, still have them all (like an idiot) up until 2005, give or take a year or so. 

Regards,
Steve

One 'like an idiot' to another.. :) ..  I Have THOUSANDS of Car magazines (back to around 1978)  I finally stopped HRM, CC, and PHR a few years ago but all those magazines organizes mostly by year/name.  I need to let them go, but can't imagine trashing them!  Woe is me...   :(
09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette, '60 Corvette, '72 Corvette
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

mrk69

  • Newbie
  • *
  • Posts: 2
    • View Profile
Re: 186 heads
« Reply #12 on: January 28, 2019, 04:12:01 AM »
You might want to check with an area auto museum. Many have automotive related libraries that would welcome donations of collections like this. I gave mine to the Gilmore Car Museum in Michigan.

firstgenaddict

  • Hero Member
  • *****
  • Posts: 2882
  • caretaker of 1971 LT1's 11130 & 21783
    • View Profile
    • Groome Family Automobiles
Re: 186 heads
« Reply #13 on: January 28, 2019, 02:47:21 PM »
They were canted toward the exhaust because that is typically where preignition occurs- thus if you fire the plug closer to the preignition points "HOT SPOTS" -  you are less likely to have colliding flame fronts(detonation) which will destroy the engine. 
 
DETONATION is the collision of two flame fronts inside of the cylinder.
I have a book which shows photos taken by GM through a quartz lens of the entire sequence. Twenty or so photos of what happens during a pre-ignition situation illustrated in crank degree BTDC and ATDC.
James
Collectin' Camaro's since "Only Rednecks drove them"
Current caretaker of 1971 LT1's - 11130 and 21783 Check out the Black 69 RS/Z28 45k mile Survivor and the Lemans Blue 69 Z 10D frame off...
https://plus.google.com/photos/112392262205377424364/albums?banner=pwa

Jcdubs

  • Newbie
  • *
  • Posts: 5
    • View Profile
Re: 186 heads
« Reply #14 on: January 28, 2019, 05:11:37 PM »
Thanks guys,
 I guess the next question is there any worth in these dinosaurs, since they have been modified?