After motor revision of this car : 200hp
5 Speed-gearbox. 
In 1971, a pilot engineer, Ken Costello, had the idea to install in the "kind" 1.8 liter MGB a more powerful engine. He turned to the Rover V8 itself from a Buick V8. This engine already fitted the Rover P6 and P5. The 3.5 liter engine then developed 180 horsepower, which transformed the MGB drastically. MG, seduced by the transformation, took the idea to his account, while reducing the power to 137 horses. Note that for three years, the Costello was produced (just 225 copies) at the same time as the factory V8. Despite the larger engine and increased performance, the behavior of the GT did not suffer from this difference, the V8 engine while aluminum is not heavier than the small 4-cylinder cast iron: on the contrary, its weight was 20 kg lower It should be noted that when this engine was produced in the United States, it was the lightest V8 ever built.

Specifications
Bodywork
Length : cm (in): 392 (154.4)
Width : cm (in): 152 (60)
Height : cm (in): 127 (50)
Wheelbase : cm (in) : 231 (91)
Weight: kg (lb) : 1084 (2390)
Mechanics.
Displacement : V8 3532 cc (Buick – Rover) (215 cu in), front-mounted
Valve gear : 126
Fuel system : 16
Gearbox : 5-speed manual
Drive wheels : rwd
Maximum power : 139 bhp at 5000 t/m
Maximum torque : 262 Nm at 2900 rpm
Top speed : 190 km/h (121 mph)