HS4 Triple Carburettors for Austin Healey 3000 MK1
If you're building or maintaining a performance-tuned Austin Healey 3000 MK1, this HS4 Triple Carburettor Set offers a complete, pre-spaced assembly for custom applications based on BN7 and BT7 models from March 1961 onwards. Although triple HS4 setups are not standard factory equipment, they are a popular period-style modification among enthusiasts seeking improved throttle response and authentic SU carburettor performance.
This set includes three new HS4 carburettors, correctly spaced, mounted, and linked for direct installation onto suitably prepared inlet manifolds. Each unit features new spindles, bushes, jets, gaskets, and linkage components for consistent and reliable operation.
Benefits
- Period-style triple-carburettor configuration for 3000 MK1 BN7 & BT7 models
- Pre-assembled with correct spacers and linkages for ease of fitting
- Improves throttle response and helps balance fuel delivery across cylinders
- Built with genuine-spec SU HS4 components for long-term reliability
- Supplied ready to install – no fabrication or adjustment required
- Ideal for custom builds, historic racing, or performance restorations
Compatibility & Fitment Guidance
This triple-carb set is intended for use on Austin Healey 3000 MK1 BN7 and BT7 models produced from March 1961 to August 1961 with a compatible inlet manifold capable of accepting three 1½” SU HS4 carburettors. It is not compatible with earlier twin-carburettor versions or later MK2/MK3 models fitted with HS6, HD6, or HD8 units. Please confirm inlet manifold type and engine number before ordering.
Why Replace This Assembly
Original carburettors and linkage assemblies often suffer from wear at the spindles and joints, resulting in uneven throttle response, air leaks, and erratic idling. This complete, rebuilt set restores synchronised fuelling and smooth engine operation in performance applications.
Technical Notes
- SU Type: HS4 (1½” bore)
- Manifold Spacing: Designed to suit late BN7/BT7-style inlet manifolds with triple mounting
- Contents: 3x reconditioned HS4 carburettors, interconnecting linkages, and correct spacers
- Installation: Pre-aligned and bench-assembled for fast fitting
Servicing & Maintenance
Service kits are available for individual HS4 units, including front, centre, and rear carburettor rebuild sets. Regular inspection of linkages and seals is recommended for optimal performance.
Note on Originality
This triple-carburettor configuration is an aftermarket performance setup and not a confirmed factory-installed system. It is most suitable for owners undertaking custom rebuilds or period-style modifications.
FAQ
Will this fit my 3000 MK1 (BN7 or BT7)?
This set is designed for BN7 and BT7 models produced from March 1961 onward, but only if your inlet manifold is designed for three HS4 carburettors. Always check the number of inlet ports and spacing before ordering.
Is this the same setup originally fitted at the factory?
The factory briefly used a triple HS4 setup in some late BN7 and BT7 models, but original parts are extremely rare. This kit uses brand-new components and is intended for performance restoration or replacement, not concours originality.
Do I need to modify anything to fit this?
If your manifold and engine bay are already set up for triple HS4s, no modification is needed. However, earlier twin-carb models or cars with non-standard manifolds will require changes to accommodate the extra carburettor.
What else do I need to complete installation?
You’ll need a suitable triple-carb inlet manifold, throttle cable or linkage to match, and appropriate gaskets and air filters. Check your existing setup before fitting.
Are these carburettors reconditioned?
No — these are brand-new HS4 units built to SU specification.