Jono.
I have a 9937263 head listed has a 173/2850 ADR27A head
4J9 means it was cast on the 4th of September 1979 so off a VB commodore I would think ( HR's and HQ are more my thing ).
If you can all bare with me on this I have been trying to sort a head ID guide out for red heads and we appreciate any comments and corrections
on what I have so far.
On the stage 1, 2 and 3 thing.
There is always a lot of different views to that one but if you have a look at this picture
http://gallery.oldho...ageViewsIndex=1and this one
http://gallery.oldho...ageViewsIndex=1That is what perfectune (Y/T) called a stage three back then.
Interesting to note in this advert stage 1, 2 and 3 heads which are listed as hand finished items and Yella Terra as a separate item and is listed as machine modified.
Rodomo I was also told that the early Y/T heads did not have Y/T on the valves and looking at that picture those valves do not have the Y/T on them.
I was told years ago a stage one had slighty over size valves and it had been throated to suit those valves. With basically minor port work done.
stage two was std inlet post removed and a insert post fitted with both inlet and exhaust ports were ported and match ported to the inlet gasket with slight larger than stage 1 valves fitted.
Stage 3 I always thought looked like this.

Where the inlet posts had been removed totally and a Hex head bolt was used instead of a std head bolt.
they also had duel springs, larger that stage 2 valves and had been decked.
But after looking back through my old magazines and finding the adverts in the links above I know that is not right.
But to add to that I have now been told that they tried the removal of the post altogether as in the picture and they had problems with the heads cracking so then they went to the insert post design instead.
Like in Jono's no 3 picture.
If you have a look here
http://gallery.oldho...ines/red heads/ I have a selection of pictures which now have to be renamed showing a std head, a slightly modified head (stage 1)and a more modified head (Stage 2 which is actually possibly really a stage 3 head)
Since doing these pictures I have been doing a pictorial record of casting numbers verse chamber designs which is here.
http://gallery.oldho...yl Casting ids/The only problem is that I have came across one casting number with two designs.
Both of these heads are modified with larger valves and the second picture is a possible Y/T head where as I am not so sure if the first one is a Y/T or not.


Both are 7429477 casting number heads one with a B97 9 2 67 date code and the other with a B237 23 2 67 date code but as you can see totally different chamber designs.
Any ideas on this anyone
So from this I am interested in any pictures I can come across of any other chamber/casting pictures that I do not have.
Cheers Paul.