“You can make a race engine a street engine, but you can’t make a street engine a race engine,” says Nick Arias, Jr. of Nick Arias Jr. Racing Components. “So we designed racing quality into the product. It’s got a real broad marketplace. You could run Bonneville or put it in a street rod.”
Beautifully crafted from A356 alloy and featuring full water jackets, these heads share many similar design features and some parts but each is specific to the respective block.
“The GM block has a 4.400-inch bore center and the Ford is 4.380, so they’re pretty close,” says Arias. “The port design and strategy are the same. The rockers and shaft-diameter carry over but the stands are different.”
The LS head has been out a couple years longer than the Ford model, but many engine builders may have let it slip from memory.
Arias is seeing renewed interest in the head. It will fit LS series blocks with a 9.240-inch deck height in addition to LSX and other aftermarket blocks — although the head does not have the extra outside bolt holes due to interference with the exhaust port.
Two different chambers are available: a 72cc standard and a Pro Stock-inspired quench-pad design with 67cc. Both have central spark plug location and high-port entry intake runners that flow up to 380 cfm out of the box and around 409 cfm with additional CNC machining. Exhaust flow is 268 cfm and 301 cfm with machining. Valve sizes are 2.250-inch intake and 1.600-inch exhaust.
“That’s right at the limit for a 4.000-inch bore,” says Arias, noting that the valve angles are 15 and 16 degrees, respectively.
Manton H-13 lash-adjusting screws.Other features of the head include stainless-steel valves (titanium and Inconel available), Manganese bronze valve guides, heat-treated ductile iron valve seats and accommodations for valve springs up to 1.650-inch diameter. The heads come complete with billet alloy stands and shaft rocker assemblies that are lubricated with oil coming up through the pushrods. The rockers are investment cast 4340 steel roller-tip designs with dual needle bearings and
Also included with the cylinder head package are pushrods, ARP head studs, Cometic gaskets, oil-drain-back kit, header flanges, gaskets and any related hardware. The engine builder will have to use Arias hemi pistons. Arias does offer a cast intake manifold that can support a Roots-style supercharger or be fitted with plates for one-two or three carburetors. Finally, cast aluminum finned valves covers with breathers, spark plug tubes and hardware come with the heads.
The Ford heads are basically the same, except for the bolt-hole locations and the intake manifold is retooled for the Ford’s right-bank-forward design. The Ford also has a thermostat manifold.
The head assemblies cost around $9,000, depending on options.
Arias also uses the Ford head in a crate-engine program offered by the company. The “A” series boasts around 500 horsepower and costs around $15,500 while the “B” series adds $2,000 to the price tag but picks up 250 horsepower. Arias also has a 1,000-horsepower custom version that is priced after customer consultation.