32 Valve Head Picture

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21400 Lassen St. Unit G Chatsworth, CA. 91311
 Tel 818.709.4781  Fax 818.709.4788

Blown '67 Camero








Motor with 32 Valves showing

(US Patent #5,007,387)

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Blown Big Block Motor




A bolt-on for all 5.0/351 and larger Windsor motors. The dual1.65" intake valves have a curtain flow area (Diameter of the valves X height of lift) of a single 3.3" intake valve and dual 1.4"exhausts equal to a single 2.8" valve. This yields flow and H.P. notattainable with a standard two valve head.
While many "race" heads are strugglingto flow 300 cfm at radical lifts of 0.700"or more, Arao Engineering Inc. hasdeveloped 32-valve aluminum cylinderheads that flow 400 cfm at just 0.600" lift!


Like other Arao Engineering 32-Valve Cylinder Heads, these not only flow more air but flow much more during the earlier stages of lift. So not only do you get more at full lift, you get far more early, which means you get more complete cylinder filling.

Combustion chamber side of head showing centrally located spark plug, two intake valves and two exhaust valves. The squish band comes in from all corners, accelerating the air towards the spark plug. Making it the fastest burn, least prone to detonation of any combustion chamber possible. With this advantage the compression ratio on pump 92 octane fuel can be half a ratio higher than with a two valve head.

In supercharged, turbocharged or nitrous applications, this also means more forced induction can be used with less chance of detonation. Also even though there is more exhaust valve area with the two exhaust valves, it is accomplished with a smaller valve. These smaller valves are less likely to glow red and pre-ignite the mixture in severe duty applications.
Notice stock head gaskets can be used, and all water holes are located in the exact same location to come through the gasket as in a stock head.

Combustion chamber volume is 64cc standard. Can be varied from 58cc to 78cc. Stock flat top pistons can be used from9.0:1 to 10.5:1. For higher compression ratios pop up piston sare available. Valve notches are required if the camshaft larger than.550" lift and 244degrees @050.
The "B" heads for 4.0" to 4.060" bore size has valve sizes of:Intakes 2@ 1.650" each. This has a curtain flow area (perimeter of valve X height of lift, the actual flow window,of a single intake valve of 3.300" diameter. And Exhaust sizes 2@1.400" each. This has a curtain flow area ofa single 2.800" exhaust valve. This is why the 32 valve heads can produce well over 100 hp more than the best2valve heads on the market today.
The way this curtain flow area works in the 4 valve per cylinder application is this. The performance gain with the 4 valves per cylinder is not so much at peak valve lift, (an engine is only at peak valve lift for a very few crankshaft degrees), but the flow advantage it has all the way up to full lift and all the way down after full lift. This is when the
cylinder is getting more fully charged on the intake stroke and more fully excavated when on the exhaust stroke.For example, at only .050" valve lift the 4 valve head is already flowing 50% more air than the 2 valve head at thesame lift.
Also camshafts can be run that have a wider lobe separation and less duration for the same application. The wider lobe separation purges less intake charge straight out the exhaust when at low speed. This less purging makes for more low end torque, less emissions, and less fuel consumption. Also camshafts with approximately 10 degrees less duration for the same application can be used. This still makes much more overall power than the 2 valve heads, but has the same RPM characteristics where the peaks occur.
Most of the time we prefer mechanical roller camshafts. This enables us to run the spring pressures that enable the extra RPM capability of the 4 valve heads. With hydraulics, the springs have to be lightened up toenable the hydraulics to work properly and this cuts into the extra RPM capability.
RPM Range
The unique valve gear arrangement made possible by Arao Performance's patented head design(US Patent #5,007,387) allows rev's to over 9000 RPM without use ofexotic valve train parts or freakish valve spring loadings.



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