Big Power CNC Aluminum Cylinder Heads
Raylar Big Power CNC aluminum cylinder heads are engineered to maximize the horsepower and torque of the big block Chevrolet Vortec 8100 8.1L / 496 engine. Typical aftermarket cylinder heads are cast and machined ensure the head surface is flat. In addition to these basic steps, all Raylar Big Power heads are further CNC machined in the valve bowls, combustion chambers, intake ports and exhaust ports. We then port match our cylinder heads, maximizing airflow through the ports. These steps are usually an additional charge with aftermarket head manufacturers, but is standard on our heads.
Raylar uses stainless steel nitrated valves for maximum wear and durability. These valves measure 2.19 / 1.75 and have thinner 11/32 valve stems to enhance airflow. These valves are set in bronze guides for maximum reliability. Our heads come with special high-lift dual valve springs with dampers, built to work with our high-lift series of camshafts and use CNC chromoly retainers. Instead of rubber seals, these heads feature viton valve stem seals for added durability.
These heads work best with our stainless steel roller rockers and self adjusting locking AFN nuts. Raylar cylinder heads are direct replacement bolt-on parts for any 496cid / 8.1L engine. All of our parts fit under the stock valve covers.
Fits Any Vortec 8.1L / GEN7 BBC 496cid:
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Our Big Power CNC aluminum cylinder heads out flow every other cylinder head on the market. Expect huge performance gains across the entire powerband.
- Lightweight A356T56 Alcoa Alloy Aluminum
- Smooth Cast, 5 Axis CNC Centers Machining
- Super Alloy Hardened High Strength Steel Valve Seats
- Manganese Silicon Bronze Valve Guides
- Super Viton In Steel "Top Hat" Valve Seals
- High Flow Necked Stainless Steel EV8 11/32" Valve Stems, Black Nitride Strength Treatment
- Intake Valve 2.19" / Exhaust Valve 1.75"
- Hardened Steel Rocker Arm Studs
- 107cc Combustion Chambers
- 315cc High Velocity Intake Port
- 135cc High Velocity Exhaust Port
- Complete 5 Angle Valve Job For Maximum Flow
We developed our CNC Extreme aluminum cylinder heads for large displacement and forced induction applications. If you are looking for maximum flow for your stroker engine, these heads are impossible to beat!
- Lightweight A356T56 Alcoa Alloy Aluminum
- Smooth Cast, 5 Axis CNC Centers Machining
- Super Alloy Hardened High Strength Steel Valve Seats
- Manganese Silicon Bronze Valve Guides
- Super Viton In Steel "Top Hat" Valve Seals
- High Flow Necked Stainless Steel EV8 11/32" Valve Stems, Black Nitride Strength Treatment
- Intake Valve 2.25" / Exhaust Valve 1.88"
- Hardened Steel Rocker Arm Studs
- 107cc Combustion Chambers
- 315cc High Velocity Intake Port
- 135cc High Velocity Exhaust Port
- Extensive 5 Axis CNC Porting
- Complete 5 Angle Valve Job For Maximum Flow
How Much HP From Ported Stock Heads?
"The stock heads are JUNK with a capitol "J"! Don't even think about trying to step the stock heads up with port work. The castings are thin, the short side radius is way to high and the combustion chamber is a total joke. The stock version of these heads are the worst I have ever seen come out GM... Raylar cylinder heads take less timing, gain over 65 horsepower and improve gas mileage tremendously!! With the new intake manifold that Raylar designed the engine gets even more efficient. The stock cylinder heads were so bad that making them better was a snap."
Darrin Morgan, Reher Morrison Racing Engines
We've tested hand ported and machine ported stock cylinder heads on the dyno. On average, you can expect somewhere between 10-15 horsepower from ported stock iron cylinder heads.
Cylinder Head FAQAdd Compression, Flow & Power
We've gone to great lengths to make improvements over the stock cast iron Vortec cylinder head. We've reshaped the 8.1L combustion chamber in the Big Power cylinder head. Our combustion chambers are smaller and more efficient, raising compression, promoting a more even burn, increasing fuel mileage, improving driveability and reducing detonation in forced induction applications. The ports are CNC machined and flow over 350cfm, allowing the 8.1L to breathe well past 6000rpm. The result is a bolt on ready 65+ horsepower and 1-2mpg improvement - if you can keep your foot out of it.
How Much Air Do Raylar Heads Flow?
Raylar big block Chevy / GMC cylinder heads out flow every 8.1L cylinder head on the market. Below are flow numbers for our standard Raylar CNC heads and our special-order CNC Extreme cylinder heads. We’ve included the Dart Iron Eagle 8.1L cylinder head in both 4.5 and 4.26 bores for comparison. Click on the image to see a larger version.
