Someone please check these out
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Postmaster
Joined: Mar 2003
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From: Spokane WA
Someone please check these out
Will someone please check these heads out and tell me what they will really do on a stock 400.....not much of a genius with heads and help would be appreciated before bidding on them.....are they streetable with premium gas (92 octane here) with or without additives on a stock 400 in a bronco?
thanks
kevin
Heads on Ebay
thanks
kevin
Heads on Ebay
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From: Indiana
They would be a great improvement over your stock heads. Your compression ratio would be in the 9.5 to 9.75 range. But since the Aussie heads have a small combusion chamber you'll get a much improve quench area in the head, so you should run excellent on 92 octane with no problems. Might even get by with 89 octane ok. Put yourself a MSD iginition box on there and I know you could use cheap gas with no problems.
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From: PacNW
Those are nice heads but there are some things to keep in mind. A factory stock 400 has the pistons sitting down in the bore >.050". In order to obtain any advantage from the quench effect of those heads the piston needs to come within .040" of the heads. Typically head gaskets are between .035" and .040" thick so the pistons need to come up to virtually "zero deck" to utilize the quench advantage.
Most rebuilder type pistons are "destroked" .010" - .020" to allow for block decking and head resurfacing which means the pistons will sit even further down in the bore. If you rebuild the bottom end you need to find out what the compression height of the pistons you're using is.
Most rebuilder type pistons are "destroked" .010" - .020" to allow for block decking and head resurfacing which means the pistons will sit even further down in the bore. If you rebuild the bottom end you need to find out what the compression height of the pistons you're using is.
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From: chicago burbs
http://raceabilene.com/kelly/hotrod/compression.html
some standard inputs are .040" gasket thickness, 4.1" gasket bore diameter for Fel-Pro blues. these are also variable depending on your choices, as are the rest of the blanks.
some standard inputs are .040" gasket thickness, 4.1" gasket bore diameter for Fel-Pro blues. these are also variable depending on your choices, as are the rest of the blanks.
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From: PacNW
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I have a 400 that I will be rebuiling shortly. I was planning on puttin in cleveland flat tops bored .030 over. Would heads like the aussie heads allow me to run regular (stock style) pistons, taking into acount the 30 overbore, and still have the high cr? I am looking for at least 9.5:1. I will be adding an MSD ignition. Lastley, would it still run on pump gas at this cr or even a bit higher? (we only have 91 around here
)
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From: Indiana
Crossbeed_65 If you plan to use Aussie heads and drive it on the street you will want to use your factory pistons. If you used flat top pistons your compression ratio would be in the 10 1/2 - 11 to 1 Great for 100 octane not good for 91 octane. Just changing to Aussie heads will amaze you how much better a bone stock engine will run. Also 351 Cleveland piston will not directly work in your 400 without some major modifications $$$ But you can buy 400 flat tops If your had your heart set on them.
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From: Houston/Hope BC
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Unfortunately 9.5:1 will require detuning to run on pump gas which negates the gains the increase in CR provides. If the engine they are going on has been decked or the heads need milling to clean them up the CR goes even higher. 
Maybe someone knows where to get 0.060 or 0.080 thick head gaskets. Stacking two head gaskets is really not a good idea.
There have been very complete discussions on these heads and quench here. To do the job right takes custom reverse dome pistons, not just dished, that conform to the shape of the combustion chamber.
Maybe someone knows where to get 0.060 or 0.080 thick head gaskets. Stacking two head gaskets is really not a good idea.
There have been very complete discussions on these heads and quench here. To do the job right takes custom reverse dome pistons, not just dished, that conform to the shape of the combustion chamber.
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From: chicago burbs
here is a partial listing of what is available under the 351C application. there is a .093 thickness also.
http://www.austrackmotorsport.com.au...%20gaskets.htm
http://www.austrackmotorsport.com.au...%20gaskets.htm
Last edited by grclark351; Mar 5, 2004 at 10:20 PM.
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From: Boise, Idaho
Kevin,
No need to be in a hurry to buy Oz heads, they come up all the time. The price on this auction is starting to creep up. Phil "Ausheads' in Portland will sell them for a good price. He's an Oz import, himself.
The difference between these heads and standard Cleveland (not the 351M/400 heads) is the shape of the chamber. The ports of the 351C heads and the Oz heads are the same. The problem is the large displacement of the 400 and the small size of the Oz chambers; compression will be too high.
Short answer, get some 351C heads (not the 351M/400 heads, but the 70-74 Cleveland heads) and spend your money on the best valve job you can get. I got some 351C heads off of ebay for $25.
No need to be in a hurry to buy Oz heads, they come up all the time. The price on this auction is starting to creep up. Phil "Ausheads' in Portland will sell them for a good price. He's an Oz import, himself.
The difference between these heads and standard Cleveland (not the 351M/400 heads) is the shape of the chamber. The ports of the 351C heads and the Oz heads are the same. The problem is the large displacement of the 400 and the small size of the Oz chambers; compression will be too high.
Short answer, get some 351C heads (not the 351M/400 heads, but the 70-74 Cleveland heads) and spend your money on the best valve job you can get. I got some 351C heads off of ebay for $25.