Need a replacement catalytic converter for your 1978 MG MGB? MagnaFlow offers high-quality catalytic converters engineered for 1978 MG MGB sub-models and engine sizes. We combine efficient design and state-of-the-art manufacturing to meet or exceed required emissions standards. Select your 1978 MG MGB requirements and state vehicle registration to buy the best MGB catalytic converter online that fits your '78 MGB and meets your state’s emissions compliance.