Six Cylinder Heads
Original submission by T Mar 30th 2007:
- 1 Six Cylinder Heads:
- 1.1 Heads:
- 1.2 Casting Numbers:
- 1.3 Casting Date Decode:
- 1.4 Stages:
- 1.5 Stage 1:
- 1.6 Stage 2:
- 1.7 Stage 3:
- 1.8 Adjustable Rockers:
- 1.9 Non-Adjustable Rockers:
- 1.10 Blue Engines:
- 1.11 Black Engines:
- 1.12 EST and EFI VK Heads:
- 1.13 Interchangeable Parts:
- 1.14 Further Head Details:
- 1.15 Links:
- 1.16 Terms:
Six Cylinder Heads:
See also the
Submitted by v8slrtorana on Tue, 27/03/2007 - 09:49.
Holden 6 cylinder heads are stamped with L & H. Low and High compression.
|Casting Number ||Engine||Additional Info ||Date |
|7420081|| 179 - 186||179 & early 186 head||5-11-64 to 30-6-65|
|7420081|| 179 & early 186 |
|92013755||2850|| 2.85 Low Compression Head|
|9937263||2850||2.85 High Compression Head||75-76 to 4-9-79|
The dates below these are dates I have casting dates for, they may have been from before or after these dates as well.
The engine types are what I have been told they are for so I would like to confirm them too. 6cyl_7420081__h? normal 179 & early 186 head
5-11-64 to 30-6-65 6cyl_7420105__L
24-8-64 6cyl_7420109__H 149
dated 25-3-64 to 4-10-65 6cyl_7429461__L
24-5-66 to 23-2-67 6cyl_7437395__L Is used for both 186 high compression and 161 low compression.
13-11-67 to 24-11-69 6cyl_7437397__L I suspect this may actually be a 395 cast head. 6cyl_7438296__H 161
18-4-64 to 16-2-70 6cyl_2811929__H 173 HG adjustable and HQ non adjustable
26-9-72 to 24-5-74 6cyl_2811930__L 202 HG adjustable and HQ non adjustable
15-4-71 to 22-3-76 6cyl_2815843__H XU-1 head P/N
14-5-70 to 27-6-73 6cyl_2817134__ 186X 6cyl_9937262__L 202 ADR27A head
5-5-75 to 7-79 6cyl_9937263__H 173/2850 ADR27A head
75-76 to 4-9-79 I would be very interested in any information for any of these heads as far as what is for what and other casting dates.
I have pictures of the chambers of a few of these Here
If anyone has pictures of the chambers of any of the others can you send them my way please. ( actually a picture of the chamber and the cast number would be even better )
Casting Date Decode:
Submission by Ben Simpson.
E186 will be the casting date. 18/5/1966 E = may 18 the 18th of may, 6 for 1966 8 is just a casting id, maybe the 8th time the mould was used that shift etc?? H for high comp
477 is what i recall as a 161 head.
End of Submission by Ben Simpson.
This refers to the amount of metal removed from the shared head ports.
The port has the Head Bolt removed as far as possible. The Head Bolt and support is still in place.
The port has the Head Bolt completely removed. The Head Bolt and support is no longer in place. A short hex head bolt is usedin the lower position of the head and a plug inserted in the top to seal the port from the atmosphere. HQ_SS Shed
The earlier 149, 161, HP, 179, 186 heads have adjustable rockers which can be an advantage.
173 and 202 use the same rocker gear as the later blue and black heads, non adjustable.
From what i know, all reds where available in either high or low comp versions, so anything is possible.
See Rockers and Pushrods.
Blue Engines:In the blues, only the 173's came out high comp.
The blue VC 173 head is probably the best to modify as it is the only high comp, 12 port non exhaust emission control head.
92013755:2850 blue low compression Head.
Black Engines:Black engines were fitted to EST and EFI 6 cylinder VK Commodores. Blacks have the low comp heads only.
The black EFI head is different to the EST head, it has no exhaust emission control and has better port work than any of the factory heads.
Unleaded petrol can only support a maximum of 9:1 static compression, so as Dusty says, fitting a high comp head might not be a good idea.
End of submission by V8slrtorana.
EST and EFI VK Heads:
Interchangeable Parts:Submitted by Qute on Thu, 29/03/2007 - 12:49.
In short, a 202 head is a direct replacement for a 186 head.
You will need to run the rocker gear and pushrods for the 202 head as the 186 gear is not compatible (the pushrods are longer in a 202 and the rockers should be obvious...).
Everything else will be a direct swap.
End of submission by Qute.