The Performance Engines catalogue gathers MGOC Spares' stage-by-stage tuned engine programmes for the principal classic MG engine families, the four-cylinder B-Series of the MGB, the A-Series of the Midget, the six-cylinder C-Series of the MGC, and the Rover V8 of the MGB GT V8. The programmes are the work of decades of development in the workshop, and the configurations have been refined to the point where each stage represents a coherent package of cylinder head, camshaft, carburation and exhaust changes that work together rather than against each other. Buying a complete stage-engine eliminates the risk that comes from collecting individual tuning parts piecemeal, the head flows what the camshaft wants, the carburettors are sized to the head, and the exhaust is matched to the breathing capacity of the whole assembly.
MGB Performance Engines
The MGB Performance Engines programme covers the four-cylinder 1.8-litre B-Series across the full production run. The standard production engine left the factory at around 95 bhp with the early high-compression specification, dropping through the 1970s as compression ratios fell and emissions controls came in. The MGB stage programme reverses that history, a Stage I engine returns the car to its early-1960s specification with a 9.5:1 compression ratio, a mild road camshaft and matched twin SU carburettors. Stage II adds a fast-road head with larger valves and improved port shapes, a more aggressive camshaft and twin HIF44 carburettors. Stage III is the fast-road specification with a fully ported head, a competition camshaft and twin Weber DCOEs or large-bore SUs.
The full programme is detailed in the dedicated MGB section of this catalogue.
Midget Performance Engines
The Midget Performance Engines programme covers the 1275cc A-Series engine fitted to Midget cars from late 1966 through to the 1974 changeover to the Triumph 1500cc unit. The 1275 A-Series is one of the most extensively-tuned engines in British motoring, the Cooper S and 1275 GT engine families share its architecture, and the volume of competition experience behind it is unmatched. The Midget stage engines bring a calibrated road-going version of that competition heritage, improved compression, larger valves, a fast-road camshaft and the appropriate carburation. The full Midget programme is detailed in the dedicated Midget section of this catalogue.
The 1500cc Triumph engine fitted to the late Midget is covered separately, with a more modest tuning programme matched to its different cylinder-head architecture and the constraints of the Triumph-derived block.
Performance Engines, Cross-Application
The wider Performance Engines section covers the cross-application engines for MGA, MGC GT and certain BMC-derived applications where the engine family overlaps with the principal MG cars. The MGA shared the B-Series with the MGB for the later production years, and engines built for MGB applications can be moved across to MGA cars with the appropriate flywheel and clutch changes. The MGC's C-Series six-cylinder is a different engine family entirely, and the dedicated MGC section covers the stage-by-stage rebuild programme for that car, the C-Series rewards careful head work and a properly matched manifold.
MGB V8 Performance Engines
The MGB V8 Performance Engines programme covers the Rover-sourced 3.5-litre V8 fitted to the factory MGB GT V8 and to the V8-converted MGBs that customers have built using the same powerplant. The Rover V8 in standard 3.5-litre form delivers strong, smooth torque, and the stage programme is calibrated around extracting more from the engine while preserving the qualities, flexibility, refinement, longevity, that made it the right choice for the GT V8 in the first place. Cylinder head work, camshaft selection, fuelling and exhaust are matched as a coherent package, and the full programme is detailed in the dedicated MGB GT V8 section of this catalogue. The technical team is available to advise on the right specification for any given car, the supporting work needed (cooling capacity, gearbox and clutch upgrades, axle work) and the realistic expectations from each stage of tune.