MG began offering the MGB GT V8 in 1973 powered by the aluminium block 3,528 cc Rover V8 engine. This engine had been used in the unibody GM 1961–1963, A-body platform Buick Special/Skylark and Oldsmobile F-85 and 1961–1962 Pontiac Tempest and was the lightest mass-production V8 in the world. Some changes were made by MG-Rover and the engine found a long-lived niche in the British motor industry.
By virtue of its aluminium cylinder block and heads, the Rover V8 engine weighed approximately 18kg less than MGB's iron four-cylinder. Unlike the MGC, the V8 that provided the MGB GT V8's increased power and torque did not require significant chassis changes nor sacrifice handling.
Both chrome and rubber-bumpered GT versions of the V8-powered MGB were produced by the factory with production ending in 1976.