Mondello Edelbrock Aluminum Cylinder Heads are the obvious choice for Oldsmobiles. Read up on cylinder head basics and then learn about what makes ours superior.
Cylinder Head Basics
What Is a Cylinder Head?
The cylinder head is located inside an internal combustion engine, where it sits above the cylinders on top of the cylinder block. Together, the cylinders and the cylinder head form the combustion chamber, which is sealed by a head gasket. Valves, fuel injectors, and spark plugs are also often mounted to the cylinder head.
What Does a Cylinder Head Do?
A cylinder head is made up of various passageways, which it utilizes to control the combustion process and cool the engine.
Controls the Combustion Process
Internal combustion engines are essentially air pumps that generate power from fossil fuel. The cylinder head’s passageways allow air and fuel to reach the combustion chamber, which is necessary for building horsepower. These channels also flow the exhaust fumes out of the combustion chamber and to the exhaust valve.
Cools the Engine
The combustion process creates a lot of heat, and one of the cylinder head’s other purposes is to cool the engine to keep the car from overheating. The cylinder head’s passageways help with this by providing the space for coolant to circulate through the cylinder head and head gasket.
Aluminum Cylinder Heads From Mondello/Edelbrock
Mondello and Edelbrock spent two years collaborating on ideas and design to create these aluminum cylinder heads, which are intended for 400 to 425 and 455 Oldsmobile big-block engines. You can also mill these head surfaces to 0.08 to 0.1 inches to decrease the combustion chamber volume for installation on 330 to 350 and 403 small-block engines.
Intake and Exhaust Ports and Valves
The original equipment manufacturer (OEM) positions of the intake entry and exhaust exit make this head unique because everything will fit with no modifications. Mondello Edelbrock heads also flow in prototype form at a 30 percent greater rate than stock ports, with the intake port at 268 cubic feet per minute (cfm) and the exhaust port at 207 cfm (compared to 230 cfm for intake and 162 cfm for exhaust on a “C” casting cylinder head).
The exhaust to intake flow ratio is 69 percent. The double-quench combustion chamber has the spark plug angled at 45 degrees and located close to the exhaust valve for a better and cleaner burning of the gases in each cylinder, producing more power and torque. The intake port is stock size and in stock location, like the “C” casting Oldsmobile heads. The exhaust port is a totally new design, which is much shorter in height to eliminate the dead area, but approximately the same width. The centerline of the exhaust bolt hole to the top of the exhaust port is 0.87 inches, while the stock “C” head is about 0.91 inches. The exhaust port is 1.54 inches wide and 1.4 inches tall.
The valves on Mondello Edelbrock heads are longer than stock OEM Oldsmobile valves. The intake valve is 4.756 inches long and the exhaust valve is 4.78 inches long, both of which will require a taller than stock valve cover. Both valves have one-piece stainless steel construction and an undercut 11/32-inch hard-chromed stem (the valve guide angle is 6 degrees). Mondello Edelbrock heads come with manganese bronze valve guides (not reamed or honed), hardened valve seats (not machined), and outer valve springs with flat wound dampeners that can be used on any hydraulic or mechanical (nonroller) camshaft, up to 6,000 RPM and 0.575 maximum lift. They also have individual exhaust port runners for positive evacuation of the exhaust, and do not have any head crossover provisions for a stove-type choke. The deck thickness is 0.625 inches finished.
Additional information about the Mondello Edelbrock Aluminum Cylinder Heads:
- The heads will accept all stock and aftermarket intake and exhaust manifolds and any type of header.
- All bolt patterns and accessory bolt pads are in stock location.
- The cylinder heads are supplied with 7/16-inch head bolt holes, but can easily be adapted for ½-inch head bolts.
- The exhaust and rocker stud holes are helicoiled for added strength and longevity.
- The combustion chamber volume is 77 cubic centimeters, but can be milled for a smaller volume if needed.
- The 356-T6 heat-treated aluminum casting is very strong and durable, and will give you significant weight savings.
- Heat-dissipating aluminum design incorporates a water jacket, allowing you to run a ten times higher compression ratio with today’s gasoline without detonation.
- The pedestal-type stock rocker arm assembly has been replaced with a 7/16-inch rocker stud and a ⅜-inch guideplate for adjustable rocker arms, and will require special-length ⅜-inch hardened chrome moly push rods.
- The heads are assembled and ready to install on your engine.
For small-block 350 and 403 Oldsmobile applications, you must use a port-matched 7111 Edelbrock Performer Intake Manifold when using Mondello Edelbrock Aluminum Cylinder Heads. The 7111 has ample aluminum for port matching and good gasket sealing. The precounterbored head bolt holes can easily be bored to a ½-inch for use on 1977 to 1980 350 to 403 and 1978 to 1985 diesel blocks being used for gasoline applications.
We have several camshafts to complement Mondello Edelbrock Aluminum Cylinder Heads in hydraulic, flat tappet, and roller designs. We also have several high-performance, high RPM engineered valve spring kits with chrome moly or titanium retainers available, plus roller rocker arm kits with cryogenically frozen cast steel roller tip and aluminum roller rockers, chrome moly push rods, ⅜-inch by 7/16-inch rocker studs, and poly locks.
ARP head stud and head bolt kits in 7/16-inch and ½-inch sizes with between 170,000 and 190,000 pounds per square inch (psi) are available, as well as extra tall valve covers, special Posi-Flo intake manifold gaskets and exhaust manifold gaskets, and rubberized cork valve cover gaskets (10-bolt hole). A new Detroit “O” ringed head gasket that’s 0.041 inches when compressed has been specially made for this cylinder head, and is guaranteed to hold up to 12-to-1 compression with half-inch head bolts or studs.