hey boys, im hoping this Question generates a big response as to the information that is out there it seems to variate evenly.
i have a 202 stage 5 street & strip bottom end +, i wont this to go from go to wo, from take off to top end
QUESTION - WHT WOULD YOU USE _ 9 OR 12 PORT HEAD.
9 port or 12 port
Started by
_daf67_
, Oct 29 2010 04:51 PM
36 replies to this topic
#2
_judgelj_
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Posted 29 October 2010 - 06:06 PM
depends, some people use 12, some 9. mostly preference. from what i have researched, blue/black 12 port heads flow just about the same as a worked 9 port. someone should probably confirm this.
#3
enderwigginau
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Posted 29 October 2010 - 07:41 PM
12port
#4
TerrA LX
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Posted 29 October 2010 - 07:52 PM
Why not use a set of heads of a VN 5ltr, you would need to convert the engine block as well tho.
#5
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Posted 29 October 2010 - 08:01 PM
i have a 202 stage 5 street & strip bottom end +, i wont this to go from go to wo, from take off to top end
That will never happen. The laws of physics and 1960's technology means you will only make usable power over part of the rev range. And if it has a "stage 5+" bottom end ( whatever that is ) then I will assume if will be higher in the rev range.
If you are serious about big HP, then get a bigger engine. But if you want to stick with the 202, then spend $4500 on a JZED head.
#7
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Posted 29 October 2010 - 09:05 PM
i have a 202 stage 5 street & strip bottom end +, i wont this to go from go to wo, from take off to top end
That will never happen. The laws of physics and 1960's technology means you will only make usable power over part of the rev range. And if it has a "stage 5+" bottom end ( whatever that is ) then I will assume if will be higher in the rev range.
If you are serious about big HP, then get a bigger engine. But if you want to stick with the 202, then spend $4500 on a JZED head.
THANKS CHOP, just to clarify- the stage 5+ is a ultimet pro bottom end that i had built by a bloke down in vic & yes its a high rever
and i had a price on the JZED and it was $7000 plus ( a devorse if i went there) this is why im after feedback. cheers dave
#8
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Posted 29 October 2010 - 09:32 PM
Hope this doesnt come up 3 times - got isp problems
but what exactly is a 'stage 5' bottom end ?
Bit more information would be usefull
but what exactly is a 'stage 5' bottom end ?
Bit more information would be usefull
#9
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Posted 29 October 2010 - 09:46 PM
Stage 5 in the old money would mean it has had more work done to it than what NASA did on the Apollo missions, unless you could find someone capable of producing a stage 6 or 7.
#10
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Posted 29 October 2010 - 09:46 PM
9 port.
#11
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#12
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Posted 29 October 2010 - 11:36 PM
12 port 
#13
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Posted 30 October 2010 - 06:57 AM
I have to admit when I heard "stage 5" I thought here we go again... a stage 5 is only something that someone decided to call a stage 5 it has no relevant meaning. I have included a couple of questions from the top of my head.
These questions need to be asked, has the block had plumbing work or mods to oil galleries?, what type of rods? full floating pistons and type? rings+bearings size type? crank had work? bore? straight cut gears, adjustable cam? solid cam/lifters and spec? oil pump? electronic type dizzy?
If this is a high price bottom end then you really want to match it in the induction/head area. Here you have multi choice and I went for the sound of weber power and when I put my foot half down people turn heads 100 ft in front of me on the street.
Cheers
Graham
These questions need to be asked, has the block had plumbing work or mods to oil galleries?, what type of rods? full floating pistons and type? rings+bearings size type? crank had work? bore? straight cut gears, adjustable cam? solid cam/lifters and spec? oil pump? electronic type dizzy?
If this is a high price bottom end then you really want to match it in the induction/head area. Here you have multi choice and I went for the sound of weber power and when I put my foot half down people turn heads 100 ft in front of me on the street.
Cheers
Graham
Edited by NZ Toranaman, 30 October 2010 - 06:59 AM.
#14
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Posted 30 October 2010 - 09:01 AM
It might be one of these engines?
http://stores.ebay.c...-RACING-ENGINES
Somewhere down in Gippsland (micksville) there was an e-bay seller listing engines in "stages".
http://stores.ebay.c...-RACING-ENGINES
Somewhere down in Gippsland (micksville) there was an e-bay seller listing engines in "stages".
#16
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Posted 30 October 2010 - 12:24 PM
looks like im on my own?
9 port has more potential. old man has his flowed to 340hp POTENTIAL, ill scan the sheet in later.
ive never heard of anything more than 290 hp potiontial out of a 12 port but will be more than happy to be proved wrong.
plus 9 ports make them sound 'right'
9 port has more potential. old man has his flowed to 340hp POTENTIAL, ill scan the sheet in later.
ive never heard of anything more than 290 hp potiontial out of a 12 port but will be more than happy to be proved wrong.
plus 9 ports make them sound 'right'
#17
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Posted 30 October 2010 - 11:06 PM
In the old days, stage was used as a general term. Generally:
Stage 1 was 0.5 HP/CID
Stage 2 was 0.75 HP/CID
Stage 3 was 1 HP/CID
Stage 4 was c. 1.25HP/CID
Stage 5 was supposed to be higher.
Fairly irrelevant these days, as the amount of torque you produce is more important. More important again is where in the rev range you make it.
Stage 1 was 0.5 HP/CID
Stage 2 was 0.75 HP/CID
Stage 3 was 1 HP/CID
Stage 4 was c. 1.25HP/CID
Stage 5 was supposed to be higher.
Fairly irrelevant these days, as the amount of torque you produce is more important. More important again is where in the rev range you make it.
#18
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Posted 30 October 2010 - 11:22 PM
Yeah i have a stage 17 bottom end, with a stage 25 cam and a stage 23 head, but only stage 12 rockers and stage 6 carbies, but its a stage 350 exhaust, will this combination work?
How much HP will it make? What RPM will it make maximum HP???
Moral of that gibberish above, you can call whatever the hell you want whatever stage you dang well want, give us some info on the bottom end as Graham said and we will get back with reasonable answers.
My opinion re head, if you want max hp whilst retaining a Holden casting, 9 port, for a quick slap together basic street engine type thing, 12 port.
Thats what i have anyway 
Cheers.
How much HP will it make? What RPM will it make maximum HP???
Moral of that gibberish above, you can call whatever the hell you want whatever stage you dang well want, give us some info on the bottom end as Graham said and we will get back with reasonable answers.
My opinion re head, if you want max hp whilst retaining a Holden casting, 9 port, for a quick slap together basic street engine type thing, 12 port.
Thats what i have anyway
Cheers.
#19
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Posted 31 October 2010 - 08:17 AM
If it's going to be used on the road most of the time, a 12 port will do the job nicely. My stick shifted LJ has run 12.7 @ 104mph with a cast iron 12 port. If you chasing every last hp that you can get, use a 9 port.
Your not on your own Greensnice, the 9 port will flow more than a 12 port.
Your not on your own Greensnice, the 9 port will flow more than a 12 port.
#20
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Posted 31 October 2010 - 10:40 AM
well i tried to keep away from this thread but i feel i also have to stand up for the 9 port we have gone basicly the same speed as warren also with a 9 port im yet to see a 12port iron head set the world on fire.and with a stage 5+ bottem end im guessing your going to set the world on fire cos when we ran the fastest it was with all the cast slugs and off the shelf stuff.
from my experiance it is easier to get a 9 port engine into the 12's than a 12port iron.
how many jzed heads did you get for $7,000 might have been with injection maybe?.
Cheers hayden
from my experiance it is easier to get a 9 port engine into the 12's than a 12port iron.
how many jzed heads did you get for $7,000
might have been with injection maybe?.Cheers hayden
#21
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Posted 31 October 2010 - 01:48 PM
It might be one of these engines?
http://stores.ebay.c...-RACING-ENGINES
Somewhere down in Gippsland (micksville) there was an e-bay seller listing engines in "stages".
hi, yes champ this is the bottom end i purchest with a little bit more extras , it seems i have upset a few people in saying its a stage 5+ "BUT" im only relaying that information to what is stipulated on the add & what is printed on my payment sheet SO please boys dont hold it against me LOL. and yes the the $7000 on the jzed was for injection, to answer the others, im running a full solid set up with race preped 45 webbers i have brought from weber performace - f2 etubes,150 mains,190 air,45 pump,4.5avx venturi,59 idle- i thought id put this info incase somone commented on the saying race prep,
but boys id like to say the feed back so far is grate & it seems so far what im reading , 9 port is wining
cheers boys.
#22
_daf67_
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Posted 31 October 2010 - 09:07 PM
I have to admit when I heard "stage 5" I thought here we go again... a stage 5 is only something that someone decided to call a stage 5 it has no relevant meaning. I have included a couple of questions from the top of my head.
These questions need to be asked, has the block had plumbing work or mods to oil galleries?, what type of rods? full floating pistons and type? rings+bearings size type? crank had work? bore? straight cut gears, adjustable cam? solid cam/lifters and spec? oil pump? electronic type dizzy?
If this is a high price bottom end then you really want to match it in the induction/head area. Here you have multi choice and I went for the sound of weber power and when I put my foot half down people turn heads 100 ft in front of me on the street.
Cheers
Graham
hi graham, ok here we go, bere with me - power hone five stage(woops) using torque plate & heat soak system (v8 super car program) , full static & third plane analysis , je full custom race forged pistons with optional micro ground ring lands , heavey duty piston pins toolsteel , plasma moly low tention nascar piston rings (with heavely reverse twist 2nd ring),high perf bearings full set flame hardened, oil system full revised to extrme blueprint program (including h/v oil pump), grind elliptical chamfers & degree to suit large valves , race h cam bearings &line bore tunnel, cnc extreme crank race prep to 4664 mill specs micropolish & retain work harden serface, race prepstarfire rods , solid cam (master grind) - bllet steel from usa, solid lifters (send specs latter) roll master straight cuts , 40 thou bore.... ok i hope thats enough info , cheers dave
Edited by daf67, 31 October 2010 - 09:13 PM.
#23
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Posted 31 October 2010 - 10:30 PM
My mate has built more 202s than i have had hot dinners (im not joking) and he has used both 9 and 12 port heads and he seems to build fast reving 9 ported head engines having said that he has built a 202 12 port and it did 12.5 down the drags straight off the trailer as others have said it all got to do with the whole set up.
#24
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Posted 01 November 2010 - 03:36 AM
Nice engine specs...
I mean you have spent so much on that and it has been built to high tolerances so I can see your dilemma.
All I can say is the head is really the secret, the cam should have been to suit this head so in my opinion you need to get some specs on all heads before purchasing.
My 12-port is an unmodified YT 12-port cast iron head that ran 12.9 from only a 1.997 60ft street car in full street trim on street tires which I am happy about but my mph maxxed at 107mph so it indicates I could run faster with a better drag setup. YT say these heads are a good base for further porting but I have never had this done so in theory I could go even better!
I have never had it on a dyno to find out hp figures sadly.
The consensus is the 9-port can make more but every now and then a 12-port pops up running fast as above, good luck on your choice mate
I mean you have spent so much on that and it has been built to high tolerances so I can see your dilemma.
All I can say is the head is really the secret, the cam should have been to suit this head so in my opinion you need to get some specs on all heads before purchasing.
My 12-port is an unmodified YT 12-port cast iron head that ran 12.9 from only a 1.997 60ft street car in full street trim on street tires which I am happy about but my mph maxxed at 107mph so it indicates I could run faster with a better drag setup. YT say these heads are a good base for further porting but I have never had this done so in theory I could go even better!
I have never had it on a dyno to find out hp figures sadly.
The consensus is the 9-port can make more but every now and then a 12-port pops up running fast as above, good luck on your choice mate
#25
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Posted 01 November 2010 - 04:21 PM
Bugger I missed out on most of this.
Huge differences between a 9-port and a 12-port, most people don't seem to appreciate that.
If you just wanna stick an unmodified head on a motor and get some grunt, the 12-port will probably suit you a bit better. They have big valves and bigger ports, a pretty different design in a lot of ways... the manifolds they have seem to be pretty shit though, beware!
A 9-port in theory would have to give you a wider power band. Too many variables to actually 'prove' that though
For actually modifying the shit out of a GM cast head, you would have to say a 9-port unit is also more forgiving. If you can get your hands on a Yella Terra cast 12-port, the story is different. The important dimensions in the cooling systems of the heads also vary a bit. I don't know about the Yella Terra units but the 9-port is better than the 12-port as far as consistently cooling the valve seats is concerned.
Horses for courses. Neither are amazing but they are really compact and can both be modified for a range of good applications, particularly the 9-port.
Huge differences between a 9-port and a 12-port, most people don't seem to appreciate that.
If you just wanna stick an unmodified head on a motor and get some grunt, the 12-port will probably suit you a bit better. They have big valves and bigger ports, a pretty different design in a lot of ways... the manifolds they have seem to be pretty shit though, beware!
A 9-port in theory would have to give you a wider power band. Too many variables to actually 'prove' that though
For actually modifying the shit out of a GM cast head, you would have to say a 9-port unit is also more forgiving. If you can get your hands on a Yella Terra cast 12-port, the story is different. The important dimensions in the cooling systems of the heads also vary a bit. I don't know about the Yella Terra units but the 9-port is better than the 12-port as far as consistently cooling the valve seats is concerned.
Horses for courses. Neither are amazing but they are really compact and can both be modified for a range of good applications, particularly the 9-port.
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