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Re: 'A' series head question. |
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Moderator  
Joined:
2001/5/3 7:04
From 48 North
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That is an A12 head as it has the original manifold bolt pattern
A14 round port head has the newer pattern
It will be good for max power at 4600 rpm on an A15
Posted on: 2013/6/6 19:07
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Re: 'A' series head question. |
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No life (a.k.a. DattoMaster)  
Joined:
2002/10/28 6:49
From under the Firmament LOL no twiglight effect BS
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a12 heart chambers with gx springs nice for A14 bottom end should go well with revvs and still have good torque due to round ports. Small ports are best used with high rod stroke ratios while oval ports with short rod stroke ratios. This becomes clear when when looking at bike vs car engines or even the SR16ve vs sr20de heads.
A14 has almost ideal road RSR so usually slightly ported round port is good
but the Oval port head will have more hp ability up high yet less midrange.
Round port heads are underrated for mainly mild streeter engines.
a14 (133mm rod / 77mm stroke) RSR 1.727
a15 (133mm rod / 82mm stroke) RSR 1.621
a12 (121.5mm rod / 70mm stroke) RSR 1.735
A14 with A12 crank (133mm rod / 70mm) RSR 1.9
last hybrid is perfect for that round port head
providing you have high rpm cam & required gear to suit
eg. comp, 38mm bike carbs, headers, ignition & fly/clutch.
Posted on: 2013/6/6 5:16
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Re: 'A' series head question. |
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No life (a.k.a. DattoMaster) 
Joined:
2002/11/26 0:38
From Las Vegas USA
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That head you have appears to be an early style that is listed in the competition catalog as SCCA H=Production. It has a smaller combustion chamber (27cc I think) which would give it a higher compression ratio. Since you have the head why not run it and see how it works.
Tom
Posted on: 2013/6/6 3:05
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Re: 'A' series head question. |
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Just can't stay away  
Joined:
2010/5/17 10:16
From brissie
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Is there any benefit running an a12 head on an a14
Posted on: 2013/6/4 5:56
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_________________
A12,4spd, mild cam ,head work, mags.
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Re: 'A' series head question. |
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Just can't stay away Joined:
2010/5/17 10:16
From brissie
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Yeah this will need one. I have noticed on the block where the oil journal is it is plugged
Posted on: 2013/6/4 5:56
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Re: 'A' series head question. |
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No life (a.k.a. DattoMaster) 
Joined:
2003/2/10 5:17
From Freo
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looks like an A12 unit,
double springs is a bonus,
all the heads are interchangeable, only some need an oil gallery modification...
Posted on: 2013/6/4 4:50
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_________________
'68 Thou Wagon,(home now) up and running
'69 2 door project, the yellow thing,
A12A Project motor, for the yellow thing.
A15 PSI Project Motor
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Re: 'A' series head question. |
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Just can't stay away Joined:
2010/5/17 10:16
From brissie
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Posted on: 2013/6/4 4:07
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_________________
A12,4spd, mild cam ,head work, mags.
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Re: 'A' series head question. |
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Just can't stay away Joined:
2010/5/17 10:16
From brissie
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The ports are all round.
Posted on: 2013/6/4 4:01
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_________________
A12,4spd, mild cam ,head work, mags.
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Re: 'A' series head question. |
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Just can't stay away Joined:
2010/5/17 10:16
From brissie
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Yeah that's what I thought also. Could an a12 head go on an a15 or a14
Posted on: 2013/6/4 4:00
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_________________
A12,4spd, mild cam ,head work, mags.
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Re: 'A' series head question. |
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No life (a.k.a. DattoMaster) 
Joined:
2010/6/29 8:11
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i believe there was also an a15 round port head?
DD will be able to tell you...
Posted on: 2013/6/4 3:54
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