heys guys,
just wanted to ask abhout a couple of head numbers......the head i got on there now i ainbt to sure what head it is the number is 7420081 (it also say along that side a224 and has a P) it revs to about 5500 granand was topld tis a stage 3 YT head..........if anyone can tell me that would be good
I got anopther head sitting in the garage with the numbers 2811930 (it also has on the side of the head M52 and has a L) i was told that was astage three YT head but if anyone can verify the two numbers i have given that would be a big help and save me alot of cash swapping and doing up heads! lol
cheers guys,
Adam
Head Numbers
Started by
_LJcaruso_
, Jun 28 2007 01:55 PM
14 replies to this topic
#2
_sunburst_metalic_
_sunburst_metalic_
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Posted 28 June 2007 - 03:10 PM
Gidday, No casting number determine if it is a YT Head or not (however the early red motor ones usually start with a 7), the most obvious way to tell is if the valves have YT in the faces there is a good chance (not 100%) that it is a YT Head, all casting numbers are Holdens if the Head went to Perfectatune it got Porting, Face Skimmed, Rocker Posts pinned and YT valves fitted and the price was set as to what stage they said it was (stage refers to the amont of work that was preformed). A lot of the work was done via machines ie the 6 Ports were honed by a big drill press machine in one go, the valves are over size stems so the guides were just bored and large stem valves fitted. Being so they were a quick way to get horspower from a standard motor with out spending big dollars. Someone doing it by hand you can spend hours with a die grinder doing port work and this costs thousands. Most of the YT heads have long lost there Yellow paint so it is really only the Ports and valves that distinguish a YT head these days. To be honest they are still a cheap option to having a engine shop port and flow bench a head. rgds Sunburst
#3
FastEHHolden
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Posted 28 June 2007 - 05:05 PM
LoneOranger was after a 2811930 head...a while ago now. PM him and see if he still needs one.
As the others said cast numbers wont tell if its YT or not...only port work, valves and springs....but it may just be a stocker modified with large valves, double springs and big ports...and at the end of the day they do the same thing.
As the others said cast numbers wont tell if its YT or not...only port work, valves and springs....but it may just be a stocker modified with large valves, double springs and big ports...and at the end of the day they do the same thing.
#4
_LJcaruso_
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Posted 28 June 2007 - 05:08 PM
well actually the head sitting in the garage has never been used so its still new....just needs to be sand blasted do th surface rust were the springs are.....but that head is yellow!
#5
_LJcaruso_
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Posted 28 June 2007 - 05:28 PM
well im waiting to see what heaad i got first becasue im puttin my triple su's on this weekend and then wanna go with a 35/75 solid...... if i put one of them in i gotta play with one headso can match valve springs, ports etc to the cam i want! soo i dunnoe yet..... but do agree with you..they all do the same thing!LoneOranger was after a 2811930 head...a while ago now. PM him and see if he still needs one.
As the others said cast numbers wont tell if its YT or not...only port work, valves and springs....but it may just be a stocker modified with large valves, double springs and big ports...and at the end of the day they do the same thing.
#6
_tuffgong_
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Posted 28 June 2007 - 05:45 PM
mate, the 2811930 head is a lj gtr head, built on the 5 of the 12 72 so it could be worth a nice little penny to the right person.
cheers john
cheers john
#7
_big_als_army_
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Posted 28 June 2007 - 11:00 PM
If the 2811930 head has an 'L' on it. Does the 'L' signify low compression?
#8
FastEHHolden
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Posted 29 June 2007 - 12:51 AM
Tuff...i have 2 on stock LH 202's...don't quite think so...2815843 is the one your after.
Big als army...yes "L" is low comp
but then according to this:
http://www.gmh-toran...u1 head numbers
Its is right for an LJ GTR..numbers gurus?
Big als army...yes "L" is low comp
but then according to this:
http://www.gmh-toran...u1 head numbers
Its is right for an LJ GTR..numbers gurus?
Edited by FastEHHolden, 29 June 2007 - 12:56 AM.
#9
_big_als_army_
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Posted 29 June 2007 - 12:55 PM
Surely an LJ GTR head would be high compression, not low?
They probably used this cast number head on all 202's from LJ's with factory 202's as they were all JL prefix blocks, not just the GTR's.
They probably used this cast number head on all 202's from LJ's with factory 202's as they were all JL prefix blocks, not just the GTR's.
#10
_LJcaruso_
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Posted 29 June 2007 - 01:55 PM
If it was a GTR head wouldn't it be a high comp head??? would it have better performance wise then a stage 3 YT head??mate, the 2811930 head is a lj gtr head, built on the 5 of the 12 72 so it could be worth a nice little penny to the right person.
cheers john
and If it were sold....what would it be worth????
#11
_LJcaruso_
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Posted 29 June 2007 - 02:05 PM
Then if "L" is Low Comp......whats "p"???? the head thats on my car now has a P on it!!!
#12
_LJcaruso_
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Posted 29 June 2007 - 02:06 PM
Then if "L" is Low Comp......whats "p"???? the head thats on my car now has a P on it!!!
#13
FastEHHolden
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Posted 29 June 2007 - 05:00 PM
got a pic?
Wasn't a GTR engine just a stocker?
Wasn't a GTR engine just a stocker?
#14
_big_als_army_
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Posted 29 June 2007 - 06:14 PM
Yeah, an LJ GTR engine was stock but apart from the GTRs, there weren't many LJs factory optioned with a 202, more often they were 173s. They must have had a special number head casting to match the JL block but as stated above, it was common to others too, not just JL blocks.
Apart from the Bathurst XU-1 heads, the standard XU-1 heads I thought were just the same as any other 202 head too, just with a different casting number then same as this seems to be with these GTR heads.
Apart from the Bathurst XU-1 heads, the standard XU-1 heads I thought were just the same as any other 202 head too, just with a different casting number then same as this seems to be with these GTR heads.
#15
_SableMet7/73_
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Posted 30 June 2007 - 07:04 PM
I was wondering if the YT stages were just concerning the extent of porting &
facing or does it mean the equipment ( screw-in studs & guide plates) ontop
of the machine work ie;stage 1-portng,facing,valves then stage 2-as stage 1
plus studs & guide plates? Havnt seen YT head for a while but got a Hi comp
9937263 '79 head, YT valves, screw-in studs,guide plates,ports cleaned up
& valve pockets relieved & squared off ports at flange.
Also have 9 port converted to 12 port by local Perth head bloke(used to be around
in the late 70s early 80s) named Luigi, 9937263 '73 Hi comp same work as above
plus .050" more shaved off face, huge exhaust ports, intake ports sort of like
Hi riser type shape & chambers have the kidney shape bump machined to a
flat edge or wall & lots of die grinder work in the bowels & runners- this 1 is
definately not good around town( too big) I dont think this 1 is YT. Oh & also
has possibly V8 springs & retainers.
Whats a 9937263 Hi comp head off?
Cheers Jono
facing or does it mean the equipment ( screw-in studs & guide plates) ontop
of the machine work ie;stage 1-portng,facing,valves then stage 2-as stage 1
plus studs & guide plates? Havnt seen YT head for a while but got a Hi comp
9937263 '79 head, YT valves, screw-in studs,guide plates,ports cleaned up
& valve pockets relieved & squared off ports at flange.
Also have 9 port converted to 12 port by local Perth head bloke(used to be around
in the late 70s early 80s) named Luigi, 9937263 '73 Hi comp same work as above
plus .050" more shaved off face, huge exhaust ports, intake ports sort of like
Hi riser type shape & chambers have the kidney shape bump machined to a
flat edge or wall & lots of die grinder work in the bowels & runners- this 1 is
definately not good around town( too big) I dont think this 1 is YT. Oh & also
has possibly V8 springs & retainers.
Whats a 9937263 Hi comp head off?
Cheers Jono
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