4-Valve Heads For Your Windsor Small Block Mustang!

So you still have a Winsdor block 5.0 or 5.8 in your Mustang and you have felt pretty left out in the past decade or so while the entire aftermarket has gone out for the Modular 4.6/5.4 engines and now even the new Coyote 5.0. You might even feel that everything’s been done, there is no more power in that old iron block.

When we saw these new 32-valve head sets for Ford small block Windsor family engines at the SEMA show last fall they stopped us in our tracks. Arao Engineering of Chatsworth, CA has designed and built these new true 32-valve, 4-valve per cylinder head sets that can bolt right onto your 302 , 351 or a punched out version of either.

The heads use a unique rocker configuration that utilizes the stock cam and pushrod design to open two intakes and two exhaust valves per pushrod. Now most people knowledgeable would immediately get a skeptical eye on how that works for very long. But the package from Arao comes with heavier duty pushrods and spring rates are designed to work well for up to 9000 rpm without what they call “freakish” spring loading.

The heads feature dual 1.65″ intake valves and dual 1.4″exhausts.  This yields additional flow and horsepower that even the beefiest 2-valve heads can offer. While many 2-valve race heads struggle to flow 300 cfm at radical cam lifts of 0.700″or more, these aluminum 32-valve head sets can flow 400 cfm at a milder 0.600″ cam lift.

And the benefit says Arao is not only the additional flow characteristics, but faster flow. And with the spark plug located in the center just like modern 4-valve heads, the combustion cycle is faster and more complete.  With this advantage the compression ratio on pump 92 octane fuel can be half a ratio higher than with a two valve head says Arao.


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.

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. The Windsor sets come with aluminum valve covers, pushrods and notched head gaskets for the larger diameter pushrods. The heads can mate up to any number of stock and aftermarket Windsor intake manifolds. Exhaust ports feature Ford hole locations that will work for most header flanges too.

Combustion chamber volume is 64cc standard. You can custom order them 58cc to 78cc. Stock flat top pistons can be used from 9.0:1 to 10.5:1 compression ratios. For higher compression ratios matched pop up pistons are available too.

On of the benefits Arao touts beyond the additional flow capabilities is that less radical cams to gain power. This pays dividends in efficiency, tuning and driveability all around while making more overall power than 2 valve heads.

The company believes in these new heads so much they have patented the designs. They claim the heads can add up to 100 horsepower just on their own on naturally aspirated engines. The packages do come in at a premium price ranging from about $4995. Oh, and they also offer a set for you Cleveland guys too!

More information www.AraoEngineering.com

About the author

Sam Haymart

Publisher and editor of Steed Publications news outlets including this one, ActivityVehicle.com, Motoring2.com, and others. He is host at TestDriven.TV and has been an auto journalist since 1994.