Keith Black pistons and I are about done with the drawings for the new 400 Hyper piston. I think Monday I will see some 3D models. First it will be a stepped dish piston. This will have the major quench area at "0" dech height, then the rest of the piston will drop below the surface. They perfer to have less aluminum exposed above the top ring land. They look kind of goofy, but I guess they work good. So the first piston will be a lower compression "0" deck height piston for the a 60cc aussie head. 9.5:1 compression ratio. Piston volume will be about 29cc. It will be a press fit 400 pin size, and no extra machining. It should be a "drop in" 9.5:1 piston for aussie heads.

I am not sure if I will go for a flat top hyper.

They will probably retail for about $250 a set.

Next move is to get some Aussie heads to offer a piston and head package.

 

This is good news, Tim. I am hoping to be ready to buy pistons and heads sometime in the near future. It would be nice to have a package already put together that takes the guesswork out of the equation. Please keep us informed.

 

"It should be a "drop in" 9.5:1 piston for aussie heads...Next move is to get some Aussie heads to offer a piston and head package."

Same goes for all the aftermarket aluminum variations from AFD, CHI and Edelbrock. The Aussie heads IMHO are the most overrated Ford heads on the planet.

 

Great news Tim!!!

But at least the Aussie heads are iron and not aluminum. I just don't like aluminum. -Just a personal thing tho... Aluminum is great for racing aps.

 

i'm not real sure what you mean by this statement. all of the reading i've done would suggest that increasing the compression ratio of these engines is the best way to gain horsepower and performance. what other method would you recommend for increasing CR? do you have one? i would certainly be interested in hearing your "expert" advice. the main problem with using aussie, afd or other closed chamber heads is that they require the use of pistons with a zero deck clearance to realize the benefits of using the heads. you can't just bolt them on and go. i, for one, would welcome the development of pistons for this application. i hope they will be available soon.

 

Since the pistons will be designed around the 60cc chamber, cleveland head style, then any head that's close in the design would still work. (with in reason) I have thought of a flat top hyper again, but if some one wants that kind of compression, then may go with the forged anyway.

I have to watch my cash flow and see how sales go. On the back burner, I am toying around with a 302 Boss piston again.

 

A compression increase should not be the main goal when considering Aussie heads. Using flat tops, taller CH pistons, larger bore, longer rods with offset bushings, decked block, milled heads, an increase in stroke, or any combination of these, up to or more than 12:1 is possible with a 400 using open chamber heads.

Since ports/valve sizes are virtually the same, the only real advantage to the Aussies is the closed chamber. Assuming everything was done correctly for proper quench, we should theoretically see a 15-20hp increase over an open chamber.

Conservatively, I'd say the 302C heads and custom pistons add at least $500 to the cost of a rebuild. Is this the most cost effective way to increase power and is there a really an increase at all? OR, does the slight reduction in airflow from valve shrouding offset the benefits of the quench design? More on this later.

Comparing the infamous Hot Rod 400 article to Tim Meyer's 400 project, I'm not able to draw any conclusions. Tim's engine made about 10 more peak HP but we don't know for sure if that was due to the Aussie heads. Camshafts were the same and compression was very close. The increase could have come from the larger valves, the 4V carb and aftermarket intake or the headers?? (not 100% positive if headers were used)

What else can I base this on? I have a 351C powered car with Aussie heads that is a total dog. The 180K mile, stock 351W in another car is faster and my 351C 4V car absolutely runs circles around both.

Now I can't blame the Aussie heads for too much. They were set up with no quench, way too much compression, stock cam, and a lousy Performer 2V intake. The ignition timing is severely retarded for it to run on pump gas so that's where I put 90% of the blame.

When this engine eventually comes apart I'll be saving the AU heads for a 331/302W stroker hybrid. They are still decent heads, fine for applications up to 400HP but not worthy of all the hype. On most engines, 351ci and larger I much prefer the 351C 4Vs or any of the aftermarket heads previously mentioned.

Oh, and when I say IMHO it stands for In My Humble Opinion which means I don't claim to be an "expert", but for what it's worth I co-manage a 351C tech forum with Dan Lee and we have over 300 members including a very welcome and informative Tim Meyer.

I'd very much like to see the pistons too. They'll make the aftermarket heads a more realistic option for engines that are much more common than the 351C. Hopefully that will lower prices in the long run.

Boss 302 pistons??

 

Yes I am considering Cleveland style pistons for the 302 comp. height. For the purpose of obviously 302s and the 351 stroker that uses the 3.85 stroke, stoke length rods and 302 pistons. Then it is easy to bolt cleveland heads on a 351W stroke. Fairly economical alternative for some of our circle track customers.

 

increasing the compression is the main reason i am considering using aussie heads. i don't want 12:1 compression, i'm shooting for something closer to 9 or 10:1. still wanting to be able to use pump gas, even if it has to be premium gas.

i realize that there are other ways to increase compression on these motors. it seems to me that milling heads and decking the block is a poor solution. this just creates problems with valvetrain geometry and also requires that the intake manifold be milled to fit.

you mention increasing the rod length/ stroke. i've drooled over TMI's stroker kit, and may invest in it down the road. but it is expensive. not sure i can justify the cost for the extra 34 cubic inches when i've still got a good 400 crank. not for a street driven motor.

i guess that leaves us with pistons. i am planning on using oversize pistons set up for proper quench. this should help me avoid any potential detonation issues. i hope TMI's new pistons can help me achieve these goals at a reasonable cost.

if aussie heads are over rated, then why are all the aftermarket performance heads (afd, chi, edelbrock) being developed based on this design? although i can't say i've heard much about the edelbrock heads yet, most people using the other 2 have only had good things to say about them. i would probably go with the afd heads myself, but $1500 bare is alot more than $200-300 you can get the aussies for. i also prefer iron heads. i know that the aftermarket ones are alot lighter, but i'm putting them on a 3/4 ton 4x4 so weight is really not a huge factor.

on a car you may be right about the 4v heads, but this may not be true on a heavy vehicle like a truck. most posts i've read on this site (and others) seem to indicate that 4v heads on a truck (street driven) just suck. the loss in velocity of the air/feul mixture translates into poor throttle response at part throttle ,where most driving is done.

these heads serve a specific purpose. they are spoken of highly in these forums because this is a truck forum and many people here want to increase performance and still be street friendly.

 

The best iron heads for a heavy vehicle are the 351C-2V open chamber heads, because they flow better at low lifts than any other head, except for the aftermarket heads. Because of the bigger valves the 351C-4V heads flow good at low lifts as well. The Aussies need some work to make them right, like bigger valves. Powerheads advertises some great figures for these heads, but I have heard that they do not always deliver these figures.
The aftermarket heads are no more based on the Aussie's than any other Cleveland style head. The chambers are different, and in the case of the CHI-3V head the ports are raised. Some of these these heads have greatly improved exhaust flow. I prefer better exhaust flow up to the max lift of the cam that I select over a small increase in compression.

 

12:1 compression was a potential number, not a recommendation. Any ratio between 8.5-12:1 is simple enough to get with careful parts selection. Milling the block or heads up to .025" will not cause any geometry or manifold fit issues. Even so, milling should not be one of the first methods chosen unless there is some warpage that needs to be corrected.

Flat tops alone give an easy 9:1. 351C KB 1.67 CH pistons can bump up to 9.5. Off-setting the rod bushing will increase again or using TM's 1.72 CH piston with a custom cut dish should get anything up to 11:1.

While TM's 434 kit represents the ultimate 400 stroker available, it's not in everyone's budget. A budget stroker would be the DIY 427/400 I've discussed many times over the years. It uses ACL pistons, early 240 I6 rods and an offset ground 4.17" stock crank. A little parts hunting and know-how is involved but can be easily done for less than $800. Tim, ever thought of offering this one as a budget alternative?

I don't know of any aftermarket heads based on the Aussie heads. The CHI 3V ports have more in common with a stuffed 351C 4V. The aluminum 2V offerings have new port designs but still have to conform to OEM port/valve locations to be compatible with piston valve reliefs and stock intake/exhaust manifolds. Combustion chamber designs are based on the Yates head chamber.

In the US, $200 Aussie heads are a rare find, but if comparing to $1080 bare Edelbrocks don't forget to factor in cleaning, magnifluxing, new guides, 3 angle valve job, pocket porting, resurfacing, machining for PC seals, screw in studs and guideplates. If a person doesn't like aluminum, there's not much else I can say.

Living with 4V heads on truck motors is pretty easy. The key is moderate cam and compression, dual plane 4V intake or dual or single plane 2V, some decent gearing and as many cu as possible.

How about your truck Dan? Did the 400 with 4Vs suck?


Here's some recent food for thought from KEC in Australia about Aussie heads and zero quench chambers.
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Torqueing Sense

The short motor of this torque monster goes together.

Building a fast street engine does not have to break the bank, the emphasis should be on torque production rather than bench racing horsepower statistics. In the real world, torque moves cars from A to B in a hurry and it is also responsible for frying the tyres at will. Perth Street Car journeyed to Kostecki Engine Centre, in Morley, to cover the build-up of an affordable Cleveland engine designed to make awesome torque thanks to a pair of KEC's new Avenger CNC ported 2V cast iron cylinder heads.


The block is bored by KEC to suit the new hypereutectic pistons.
The standard bores were taken out 30-thou to clean them up; the required clearance was then allowed for the hypereutectic pistons. In the interests of further dollar savings, the standard rods were re-sized and fitted with new ARP bolts. The crank was also left at the standard 3.5-inch stroke, rather than opting for a more expensive offset ground stroker combination. Plenty of torque can still be produced with a standard stroke 351. Compression, both static and dynamic, has a huge bearing on torque output because, after all, cylinder pressure creates the force on the top of the piston which rotates the crank the greater the force, the greater the torque. To ensure that the engine runs vibration free, the pistons and rods are balanced to allow the crankshaft to be correctly bob-weighted so that it too can be balanced on KEC's Pro Bal machine.


The short motor is fully assembled using standard stroke crank, standard rods and ARP fasteners.


KEC's CNC 2V cylinder heads feature a unique zero-quench combustion chamber to eliminate secondary detonation. Intake and exhaust ports and combustion chambers are CNC machined.
Cylinder pressure can be generated by increasing the static compression ratio but with today's lowoctane fuels there are certainly limits to streetable squeeze and in this case that number is 9.5:1 with a strict premium unleaded diet. The other way to generate greater cylinder pressure is with careful camshaft selection. Maximising the time that each cylinder is allowed to fill and then be compressed across the broadest possible rev range will create a torque monster that truly feels fast on the street and strip. The team from KEC, has spent countless hours dyno testing and developing camshafts for a wide variety of engines but none more than the humble Cleveland (KEC's engine of choice for their National Record holding G/Gas Mustang). The Cleveland's unique cylinder head flow characteristics require a very specific camshaft to make high cylinder pressures without the dreaded detonation.

For the ultimate budget street torquer, Team KEC selected a flat tappet hydraulic camshaft with only 212-degrees of duration at 50-thou of lift. This may seem like a very short duration, given that performance camshafts normally start at around 240-degrees but large valve overlaps only bleed-off cylinder pressure at low and mid range rpm. For those that want to raise the power band a little in the rev range, there is also a 224-degree option.

Affordable engines in Australia rarely feature aluminium cylinder heads so this stump puller is fitted with KEC's new Avenger CNC ported 2V cast iron heads. These start life as 302 closed chamber heads which are then bolted into the 5axis CNC mill where the intake ports are cleaned up around the guides and short turn radii, the exhaust ports are re-shaped and the combustion chambers are opened up to decompress the engine to the required 9.5:1 ratio.


Andrew tests the CNC 2Vs on the Superflow 600 flow bench to maximise port velocity.
There is more to these chambers than simply dropping compression though, their design is brand new and it stems from the years of R&D that was poured into the race car's cylinder heads. The race engine makes around 750 hp with a single 750 carburettor using 4V Cleveland heads - no mean feat. The benefit of spending so much time developing a race head is that it allows their best features to be incorporated into street performance heads. That is exactly what happened with the CNC Street Avengers. KEC discovered that Cievelands running unleaded fuel like a hemi-style head best, with no quench area at all. They found that even a small quench area led to secondary detonation, which is why the entire quench area is removed on the CNC mill. These are not all-out power heads. They have been designed to maximise port air speed to aid cylinder filling and boost torque using standard 2V valve sizes. Port flow has been lifted dramatically in both the exhausts and intakes without significantly increasing port volume. The Street Avengers come fully CNC ported and can be bought separately for $990.



The CNC 2V heads are torqued to the required settings as the long motor comes together.
The cylinder heads will be fitted with Yella Terra roller rockers for accurate timing and reduced frictional losses. Up top, is a brand new 600 vac sec, sitting on an Edelbrock Performer dual plane manifold. An Accel electronic ignition will ensure reliable spark and ignition timing.

A look at the engine dyno figures tells the real story - 363 hp and 403 ft/Ibs of torque are impressive figures for a standard stroke Cleveland. The torque curve rises to just under 400 Ibs/ft at only 3500 rpm which it holds for a full 1000 rpm. At maximum rpm the engine is still producing 300 Ibs/ft of torque. Horsepower too hits 300 at just over 3900 rpm, rising to a peak of 363 at 5400 rpm and maintaining 344 hp at the redline. This is a true street engine that will haul even the heaviest Falcon with ease thanks to its huge torque output. That will put a smile on your face and your bank manager's!


The finished motor is run-in and
fine tuned on the Superflow engine dyno with excellent results.


These two charts plot the increase in flow between the new CNC 2V intake and exhaust ports and standard 2V ports. The emphasis is not on absolute flow but rather maximum port velocity for optimum cylinder filling and torque production.

 

I never did any heavy loads or towing with my truck when I had the 4V Cleveland heads. I have a 3.25:1 rear ratio. The only problem that I had was with the 91 Octane fuel in California, and that was only if the motor got hot sitting in traffic, until I added an electric fan. I had about 10.4:1 static CR, but with a 72 degree ABDC IVC, the DCR was down to about 7.9:1.

I went to alloy heads so I could keep the high CR, but use a cam with less duration and earlier valve closing. The present cam is a hydralic roller with 0.595" lift and IVC of 66 degrees ABDC. At present it has 10.3:1 Static CR and 8:2:1 Dynamic CR. It runs great on 93 Octane available here, and I can occasionally mix 89 into the tank.

I used to make the tires squeal from a rolling start with the 4V Clevelands, now the whole rear end will come loose. This has as much to do with the increased torque at low RPM from the cam, as from the improved head flow.

When I get my EFI conversion done, I should pick up a little gas mileage as well. That along with the new 21 gallon tank, should improve my cruising range. I am anxious to get it on the road. It has been so mild here this winter, that there is no reason not to drive it. Just this past weekend I saw a couple of '50s and '60s muscle cars driving around.

 

I don't know about the Aussie heads,the only place I've ever heard of them is on this site.As far as closed or open chamber heads,that have no port work or anything,the compression or horsepower isn't worth worrying about.I say if you have a nice pair of open or closed chamber heads,port,polish,and up comp ratio,and they'll do a fine job for less cash than the Aussie heads.Good power from an engine comes from how well you put together your air intake components anyway,the bottom is just a compressor...

 

I have gotten the 3D model of the head of the piston. If any one would like to see, send me a Email. I will forward you the file, and the link to download the viewer software.

 

It's true that the heads are the key to making power with any engine however it's not as simple as that. Yes basically an IC engine is a big air compressor so getting the air in & out is the most important factor however there's 1 big difference. The IC engine has to create it's own power unlike an air compressor which has an external power source.

Creating power requires the burning of fuel, in this case gasoline & air and the more efficiently that fuel is burned the more power can be made. Now the key to burning fuel efficiently lies in how well the heads flow and when the fuel burns so you can't simply focus on 1 part of the equation without taking the other part into account. You can have the best flowing heads in the world but if you neglect the flame propagation and timing then you're going to get an engine that self destructs very quickly. Conversely if you have heads that burn very efficiently but don't flow well then you won't make much power.

My personal opinion is that a small, fast burning combustion chamber is the place to start. Get the pistons up to the proper height to achieve decent quench and then work on making the heads flow well. That includes a good valve job. The valves spend most of their time somewhere between open & closed so how they flow when they're wide open is not the key. Focusing on flow numbers at partial lift should give you the best bang for your buck and the valves themselves are an integral part of that. I've heard numbers as high as 50% of the increase in efficiency is due to the valve job. When you hear terms like "back cutting, swirl polishing, 5 angle" they're all about the work actually done on the valve. The problem with small comb. chambers is that valve shrouding is more of a problem than on big open ones so it takes some careful work to resolve that problem.

BTW this is only scratching the surface. There's also intake & exhaust port size, cam timing issues which determine static vs. dynamic C.R., stroke length and amount of time the piston remains at TDC, etc, etc.