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- USA
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Ships within 48 hours · Estimated delivery Jul 5 - Jul 10
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Description
Holley Single Plane EFI Intake-GM LS1/LS2/LS6 - Black - 300-137BKOverview: Single Plane EFI LS Intake Manifold. All GM LS Gen III or IV engines equipped with LS1 LS2 LS6 style cathedral port cylinder heads. Black Ceramic Coating to provide you with that aggressive look in your engine compartment. Features: Black ceramic coating provides an aggressive look to your engine compartment 2500 7000 RPM power band 4150 Square bore flange Optimized runner layout and constant cross sectional area broad torque curve, best
Overview:
Single Plane EFI LS Intake Manifold. All GM LS Gen III or IV engines equipped with LS1/LS2/LS6 style cathedral port cylinder heads.
Black Ceramic Coating to provide you with that aggressive look in your engine compartment.
Features:
- Black ceramic coating provides an aggressive look to your engine compartment
- 2500-7000 RPM power band
- 4150 Square bore flange
- Optimized runner layout and constant cross sectional area - broad torque curve, best vehicle performance from 2500-7000 RPM
- Minimum carb flange height - fit in vehicles with minimum hood modifications
- Cast aluminum construction - great manifold for centrifugal blower, turbocharged or NOS power adder applications
- Efficient casting design - lightweight, consistent wall thicknesses, improved casting quality
- Weight - 11.5 lbs.
- Height (front) - 5.417" to the lifter valley cover flange at the engine block front flange
- Port size - 2.50" height x 1.15" wide
- Includes Viton® O-ring intake to cylinder head gaskets - Viton® is a registered trademark of DuPont Performance Elastomers
- Kit does not work with factory fuel rails and requires the use of Holley Fuel Rail Kit P/N 534-219
Application:
| Year | Make | Model | Submodel | Engine Size |
|---|---|---|---|---|
| Universal |
Specs:
| Brand | Holley EFI |
|---|---|
| Construction | Cast |
| Emission Code | 4 |
| Engine | GM Small Block Gen III/IV (LS Based) |
| Finish | Black |
| Front Height | 5.417 inch |
| Fuel System Type | EFI |
| Manifold Type | Single Plane |
| Product Type | Manifold |
| Rear Height | 5.417 inch |
| RPM Power Band | 2500-7000 |
| Warranty | Limited 90 Day |
Shipping Notes
- Free Standard Shipping on $100+ Orders to the USA.
- Except Preorder products are shipped in 48 hours.
- Delivery to the USA:
- Standard Shipping : 3-10 business days
- If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
- We offer a 30-day return/exchange service after receiving.
- Final sale items are not eligible for returns or exchanges.
- To process your return/exchange, please contact us at [email protected]
- Please click here for more details>>> Return & Exchange Policy
4.4 ★★★★★
Based on 1525 reviews
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Product Reviews
★★★★★ 4
Works quite well, dose still a bit high for me
Used to take the Natrol 5mg slow release, now that I can compare these 2, I love this more. It doesn't make me feel too edgy, it's quite relaxing actually. I still have to halve the dose as the full dose makes me groggy the next day. Where the Natrol gave me very vivid, but not unpleasant dreams, these don't make me dream as vividly. It does take a bit longer to get me to sleep, but once asleep, your asleep. Highly recommend, once I finish this bottle, I'd get the 2mg tr next time, as a lower dose works better for me.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on July 10, 2014
★★★★★ 5
Excelente Muy Satisfecho
Servicio excepcional, cuidadoso, el producto muy bien empacado. Y el tiempo de entrega fue el acordado. Y del producto ni hablar, excelente.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on February 3, 2026
★★★★★ 5
seems to work just fine
Helps me sleep. I also use Mg, B complex and medical cannabis oil before bed. My sleep isn't great otherwise here in the good ol' USA (unlike in Europe where I sometimes go for complicated issues/not vacation; which indicates issues with the much higher radiofrequency exposure allowed in the US than in the European country where I sleep like a happy baby). Just wait for 5G, then I probably need to reinvent my sleep protocol if I want to get any rest. But well, with the 5G impact on the biosphere, we may not be here much longer then. That means we better stop 5G before it's all roleld out.
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Reviewed in the United States on August 2, 2019
★★★★★ 5
The product is worth purchasing!
I find that the time release melatonin works for me. The cost is reasonable, shipping directly to the home works well.
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Reviewed in the United States on September 6, 2025
★★★★★ 3
Average product
This works fine, but not as well as other time release melatonins. Recommend you do a time release with a higher level of melatonin. Round shape is more difficult to swallow
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on August 12, 2024
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