Intake Manifold 300-137 For Single Plane EFI - GM LS1/LS2/LS6 With Fuel Rail Kits | SPELAB
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Product Information +
- Brand: SPELAB
- SKU: SPIS08511-IS08512
- Availability: Many in stock
- Product Type: Intake Manifold
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PLEASE NOTE!
The SPELAB single-plane mid-rise EFI intake manifold kit is designed for GM LS Gen III and Gen IV engines equipped with LS1, LS2 or LS6-style cathedral-port cylinder heads. Its aluminum single-plane layout, 4150 square-bore flange and 2500–7000 RPM operating range make it suitable for performance-focused naturally aspirated and forced-induction LS builds.
This kit includes the intake manifold, fuel rails, fuel connection components, runner seals and mounting hardware shown in the product images.
Product Highlights
- Fits GM LS Gen III and Gen IV engines with LS1/LS2/LS6-style cathedral-port cylinder heads.
- Single-plane mid-rise design intended for mid-to-high RPM performance.
- 2500–7000 RPM recommended operating range.
- 4150 square-bore throttle-body flange.
- Cast aluminum construction with a satin finish.
- Machined injector bosses for EFI applications.
- Includes matching fuel rails and fuel connection components.
- Suitable for naturally aspirated, turbocharged and supercharged engine builds.
- Compact flange height helps reduce hood-clearance requirements compared with taller Hi-Ram systems.
Engine and Cylinder Head Compatibility
This manifold is designed around the engine and cylinder-head configuration rather than one specific vehicle platform.
- GM LS Gen III and Gen IV engine architecture
- LS1-style cathedral-port cylinder heads
- LS2-style cathedral-port cylinder heads
- LS6-style cathedral-port cylinder heads
- Standard-deck LS engine applications
Common Vehicle Applications
Common applications may include LS-powered Chevrolet Corvette, Chevrolet Camaro, Pontiac Firebird, Pontiac GTO and Cadillac CTS-V models. It may also be used in compatible LS engine swaps and custom performance builds.
Vehicle model alone does not guarantee fitment. Confirm the cylinder-head port style, engine deck height, throttle-body pattern, injector configuration, fuel-system layout, accessory clearance and available hood space before ordering.
Performance-Oriented Single-Plane Design
2500–7000 RPM Operating Range
The single-plane runner arrangement is designed for performance-focused engines operating primarily in the mid-to-high RPM range. It is best suited to builds where high-RPM airflow is a greater priority than maximum low-speed torque.
Constant Cross-Section Runner Layout
The runner layout uses a consistent airflow path between the central plenum and cathedral-port cylinder-head openings. This configuration is intended to support balanced cylinder filling across a broad performance RPM range.
Forced-Induction Compatibility
The aluminum construction and single-plane layout make this manifold suitable for compatible turbocharger and supercharger applications. Final boost level, fuel delivery and engine calibration must be matched to the complete engine combination.
4150 Square-Bore Flange
The upper mounting flange accepts a compatible 4150-pattern EFI throttle body. The throttle body and throttle-body gasket are not listed as included unless shown or stated separately.
Product Specifications
| Product Type | EFI Intake Manifold Kit |
| Intake Style | Single-Plane Mid-Rise |
| Engine Architecture | GM LS Gen III / Gen IV |
| Cylinder Head Port Style | LS1 / LS2 / LS6-Style Cathedral Port |
| Fuel System Type | Electronic Fuel Injection |
| Recommended RPM Range | 2500–7000 RPM |
| Throttle-Body Flange | 4150 Square-Bore Pattern |
| Material | Aluminum |
| Finish | Satin |
| Reference Manifold Height | Approximately 4.95 Inches |
| Reference Port Size | Approximately 2.659 Inches High × 0.918 Inches Wide |
| Injector Provision | Machined EFI Injector Bosses |
| Fuel Rails | Included |
| Recommended Applications | Naturally Aspirated and Forced-Induction Performance Builds |
| Reference / Interchange Number | 300-137 |
Fuel System Compatibility
The kit includes matching aftermarket fuel rails for use with this manifold. The factory fuel rails are not intended to mount directly to this intake manifold.
Before installation, confirm the following fuel-system details:
- Fuel-injector body style and overall height
- Injector upper and lower O-ring dimensions
- Fuel-rail inlet and outlet fitting sizes
- Fuel-line and regulator configuration
- Required fuel pressure and total fuel-flow capacity
- Clearance between the injectors, rails, throttle body and surrounding components
Fuel injectors, fuel-pressure regulator and EFI controller are not listed as included unless shown or stated separately.
Construction and Package Contents
The manifold uses an aluminum casting with machined cylinder-head mounting surfaces, cathedral-port runner openings, injector bosses and a centered 4150 square-bore flange.
This kit includes:
- Single-plane aluminum EFI intake manifold
- Left and right fuel rails
- Braided fuel connection line
- Fuel-line fittings
- Fuel-rail brackets and mounting hardware
- Eight runner O-ring seals
- Intake manifold mounting bolts and washers
- Threaded plug
- Components shown in the product images
Throttle body, fuel injectors, fuel-pressure regulator, sensors and engine-management components are not listed as included unless shown or stated separately.
This Product Is Best Suited For
- GM LS Gen III or Gen IV builds using cathedral-port cylinder heads.
- Performance street, street/strip and competition-oriented LS engines.
- Engine combinations intended to operate primarily between 2500 and 7000 RPM.
- Turbocharged or supercharged LS builds requiring an aluminum single-plane intake.
- LS engine swaps using a compatible 4150-pattern EFI throttle body.
- Builders who need a manifold kit supplied with matching fuel rails.
- Applications where a lower manifold height is preferred over a taller Hi-Ram system.
Important Compatibility Notes
- This manifold fits cathedral-port cylinder heads and does not fit LS3/L92-style rectangular-port heads.
- Factory fuel rails are not designed to mount directly to this manifold.
- Confirm injector compatibility before assembling the fuel rails.
- A compatible 4150-pattern throttle body is required.
- Throttle linkage, electronic throttle control and wiring requirements depend on the selected throttle body.
- Hood, cowl and accessory clearance must be checked for the individual vehicle.
- Vacuum, MAP sensor and PCV connections may require application-specific fittings or routing.
- ECU calibration may be required depending on the throttle body, injectors, fuel system and complete engine combination.