Free US Shipping·Ships in 24 Hours from CA & GA·30-Day Free Returns·1-Year Warranty
- Free shipping, ships within 24 hours from our California & Georgia warehouses
- 30-day free returns, we pay return shipping
- 1-year warranty on casting defects
- Made in our own factory, leak-tested and inspected before it ships
300-122 Hi-Ram EFI Intake Manifold for Cathedral Port LS
A 92mm Hi-Ram EFI intake manifold for GM LS1, LS2 and LS6 engines with cathedral port cylinder heads (5.7L / 6.0L, standard deck). Built for big-cube, high-rev race engines where hood height isn’t a limitation.
- Long runners with an as-cast tapered cross-section that works across a wide range of engine combinations
- Longitudinal plenum top
- Included fuel rails machined for -8 AN O-ring fittings, with passages large enough for high fuel flow and to help dampen pressure pulsations
- 92mm throttle body opening
See It in Action
The 300-122 Hi-Ram featured by one of the YouTube creators we work with.
“Made so much power I snapped an axle on my 2014 Camaro SS.”Sean S., verified Haytalras customer
Before you order, please note:
- Fits cathedral port LS1 / LS2 / LS6 heads only. For rectangle port LS3 / L92 heads, see our 300-116 or 300-117.
- A modified hood (cowl or hood cut) will be required for most vehicles.
- OE LS fuel injectors may not fit properly in the Hi-Ram fuel rail assembly; different spacers or brackets may need to be purchased separately.
Specifications
| Part Number | 300-122 |
|---|---|
| Engine | GM LS1 / LS2 / LS6 (5.7L / 6.0L) |
| Cylinder Head | Cathedral Port |
| Block Deck Height | Standard deck |
| Intake Style | Hi-Ram |
| Throttle Body Bore | 92mm |
| Fuel Injection | Multi-port EFI |
| Fuel Rail Fittings | -8 AN O-ring |
| Manifold Height (front / rear) | 12.32 in |
| Basic Operating RPM Range | 7,000–8,000 |
| Material | Aluminum |
What’s Included
- 1 × Hi-Ram intake manifold
- 1 × fuel rail kit
- Additional parts as shown in the product photos
Why Haytalras
- Built in our own factory. We cast and CNC-machine our intake manifolds in-house. The same factory has produced intake manifolds for Holley, TSP and Professional Products.
- Checked before it ships. Every manifold goes through air-tightness, dimensional and visual inspection.
- Ships from the US. Free shipping from our California and Georgia warehouses, out the door within 24 hours, usually delivered in 3–7 days.
- Backed by us. 30-day free returns and a 1-year warranty on casting defects.
Frequently Asked Questions
Will this fit my LS3 or L92?
No. The 300-122 is for cathedral port heads (LS1, LS2, LS6 and similar). LS3 and L92 use rectangle port heads; choose the 300-116 or 300-117 instead.
Will it fit under my stock hood?
In most vehicles, no. Hi-Ram manifolds are tall (12.32 in), so plan on a cowl hood or hood modification.
Can I reuse my factory injectors?
OE LS injectors may not fit properly in the included fuel rails and may need different spacers or brackets. Check your injector length and O-ring style before installing.
Not sure it fits?
Email haytalras@gmail.com with your vehicle, engine and cylinder head casting number and we’ll confirm before you order.
Download the official Haytalras installation instructions for this 300-122 part. We recommend reading them and doing a test fit before final assembly.
View / Download Installation PDF
Questions during install? Email haytalras@gmail.com with your engine and part number and we'll help.
Shipping
- Orders ship within 24 hours on business days from our US warehouses in Ontario, California and Bloomingdale, Georgia.
- Most US orders arrive within 3–7 days after shipping. A tracking number is emailed as soon as your package leaves the warehouse.
- Need a part urgently? Email us and we'll check stock at the closest warehouse.
Returns
- Eligible items can be returned free of charge within 30 days of delivery.
- Please contact us at haytalras@gmail.com before sending anything back so we can set up your return.
- We recommend a test fit as soon as your package arrives, before final assembly.
Full details: Returns & Warranty
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