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Discussion Starter · #1 ·
which aussie heads would be good for a moderatly built 351C. I dont want extreemly high CR because I want the engine streetable. Any suggestions for any type of head would be good, and casting numbers would be much appreciated as well.
 

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Usually when we speak of "Aussie" heads ... it's the Australian 302 heads with about 59cc chambers. I believe aussie open chambers are out there, but I don't know the cc of these heads.

My gut instinct is, in order to lower compression you could go to a slight dish in the piston and not lose the "Quench" affect and possibly get down to a compression compatible with midgrade (and possibly regular) fuel.

These heads with pump "premium" should be fine on any 351C though, assuming flat top pistons.
 

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Really aussie heads are from the 302 cleveland... I didn;t know that. They will work on my 351 clevland? I believe that I have 4v open heads that have just been rebuilt about 5000 miles ago and now that I have learned more about the heads I now know I should get the aussie ones for the street. I have dish pistons, with the aussie heads what will my comression be raised to? And where is the chepest place to get a pair? Thanks
 

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Powerheads offers Aussie heads built for $975, $1375 ported. The website is www.powerheads.com. Summit Racing has a forged, dished piston rebuild kit that gives 8.35:1 CR w/ 76.2cc heads. That should give you about 9.57:1 with Powerheads's 62cc chamber.
Powerheads lists the flow numbers for these heads, but I'm not sure if the numbers were measured at standard pressure. Another article on fordmuscle.com reports that some of their 289 heads were not measured at 28", but at 25". That would tend to inflate the actual flow numbers at 28".
Does anyone run the Aussie heads from Powerheads? I am considering them.
 

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the 59cc 2v quench heads on a 351C will give you around 10.4:1 with flat-tops if the valve reliefs are about 2cc My car can run 98 octane without detontion
 

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On 2002-05-01 07:29, speedar wrote:
the 59cc 2v quench heads on a 351C will give you around 10.4:1 with flat-tops if the valve reliefs are about 2cc My car can run 98 octane without detontion
Our trusty compression ratio calculator right here at FM shows compression to be 11.23:1

My 351C4V with 60cc chambers figures at 11.1:1 on this and other comression ratio calculators ...

I don't think 10.4 is the number
 

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Aussie 302C heads are basically a 4v style quench chamber with 2v ports and valve sizes.

You'll need a 2v intake, and most likely 2v headers. It may be possible to fit 4v headers on the 2v port, but it would be marginal at best.

My bro got some Aussies from powerheads. Cost alot, and they came with a really crappy valve spring setup. The 4v size valves had been installed, but no machining had been done to match the big seat into the bowl.

In retrospect, it would have most likely been better to buy bare castings and build them from scratch. Woulda saved some $$ and alot of hassle.

Greg

_________________
'71 Torino GT w/351c/C4

Soon to be 466/C6

<font size=-1>[ This Message was edited by: Greg P on 5/2/02 6:02am ]</font>
 

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Discussion Starter · #14 ·
Does anyone have the casting numbers for a 4v and for the 2v. also, what are the best stock castings if I want around 10 on compression. I have flat top pistons with reliefs, bored 30 over. This would be for a moderate street engine.
 

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In order to get to 10:1 you'll need more than "valve reliefs" you'll need "dishes" ...

These Aussie heads have even smaller chambers than American 4V quench heads ... Drives compression even higher ... The beauty of this is you can still run fine on pump premium fuel, these heads will tolerate the high compression.

I'm not all together sure they have and recognizable casting numbers on them ... Mine are in the attic (while I deal with my current engine building project), so I can't check them real easy. You just want the best matched pair of Aussie 302 quench heads you can find ... shouldn't be a problem to identify.

I would not recommend going to 4V valves ... You'll need to do some fairly extensive chamber work to insure there is no "shrouding" problem ... as said before these chambers are even smaller than American quench chambers.

Also as said before ... Use 2V intake and headers with these heads, 4V stuff will bolt on and even seal, but is not designed to work well with the smaller ports of the 2V, You'll be giving away performance if you do that.
 

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Really the only sure way to tell if you've got a 302 head is to look at the combustion chamber which is small(Nominal 58cc according to my '82-'85 XE Falcon workshop manual)and small 2.04/1.65 valves.
Ive got three untouched 302's kicking around in my shed and the heads seem to have different markings on all of them. One set has a 3 on the top corner outside the rocker cover rail much like the 2 or 4 you get on 2V and 4V heads. Ive also seen this 3 on garden variety open chamber 2V's too so that don't help. One thing they all have is an Aussie engineering number cast onto the underside of one the middle intake runners which, instead of the usual D1** type code you have ARD1AE....I imagine the AR means Australian Revision D1AE.
The thing is I don't know if the aussie Open Chamber 2V heads have the same engineering number? Any other Aussies listening with a late 351 head they can look at?

Pete.
 

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Don't fall for the hype! I'm running the 1970 4V closed chamber heads at 11:1 compression on the street and wouldn't even consider anything else. With 91 octane and a well tuned Holley 750 I get no detonation and it has incredible mid tourque with a 2000 RPM stall converter. It pulls like an animal from 40 MPH in 3rd gear (C4 with 3.00:1 axle ratio). Try em; you won't be disapointed!! I'm running a Comp Cams 280H Magnum, and it could easily have more cam and still be good for the street.
 

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On US 2v heads, 4v headers will fit, and will seal well if used with a good header gasket (I like the Mr G ultra-seals). I used to use my Hooker super comps for the 4v heads on my 3=2v heads all the time. And they actually sealed better on there, than on the 4v heads. However, those headers are too big for a street car, you would need something with smaller primaries.
 
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