Need a replacement catalytic converter for your 1981 Checker Marathon? MagnaFlow offers high-quality catalytic converters engineered for 1981 Checker Marathon sub-models and engine sizes. We combine efficient design and state-of-the-art manufacturing to meet or exceed required emissions standards. Select your 1981 Checker Marathon requirements and state vehicle registration to buy the best Marathon catalytic converter online that fits your '81 Marathon and meets your state’s emissions compliance.