Need a replacement catalytic converter for your 1991 Buick Roadmaster? MagnaFlow offers high-quality catalytic converters engineered for 1991 Buick Roadmaster sub-models and engine sizes. We combine efficient design and state-of-the-art manufacturing to meet or exceed required emissions standards. Select your 1991 Buick Roadmaster requirements and state vehicle registration to buy the best Roadmaster catalytic converter online that fits your '91 Roadmaster and meets your state’s emissions compliance.