The Holley GM LS7 modular Hi-Ram lower manifold is a cost-effective alternative to fabricated sheet metal for high-performance applications where induction system height isn't limited. Paired with high-flowing LS7-style cylinder heads, it's built for N/A or forced-induction engines making max power at 7,000-8,000+ RPM, with aggressive, race-bred styling for drag race, muscle car, marine, off-road, pulling truck, and street rod applications.
Specifications:
- Basic Operating RPM Range: 3,500-8,000
- Engine: GM LS7
- Fuel System Type: Carbureted
- Manifold Type: Hi-Ram (Lower/Base only)
- Finish: Natural
- Material: Cast Aluminum
- Runner Length: 6.29", tapered 4.67 in² to 2.84 in² cross-section
- Port Size: 2.49" height x 1.21" wide
- Part Number: 300-228
This carbureted base is intended for racing, performance, and street rodder applications where hood clearance isn't a consideration.
Compliance: This part is legal for sale and use on Racing Use Only Vehicles — competition vehicles that are not registered and never operated on the street. It is against the law to install this part on an Emissions Controlled Vehicle (1966-and-newer California-certified or 1968-and-newer federally certified vehicles).
FAQ
Is the Holley 300-228 street legal?
This part is legal for sale and use on Racing Use Only Vehicles only — it may not be installed on an emissions-controlled street vehicle.
What engine does the 300-228 fit?
The GM LS7 engine, using LS7-style cylinder heads.
Does the 300-228 include the plenum top?
No, this is the carbureted lower manifold base only.
