This custom designed aluminum heat shield is pre-formed to fit all Flowmaster 70 Series Big Block II performance mufflers and attaches easily with included stainless steel muffler straps. Adding a heat shield to your muffler gives added protection in reducing exhaust heat radiated through the mufflers and also helps reduce interior noise. May fit all mufflers with an approximate case thickness of 5.00 in.es tall, 11.00 in.es wide and 22.00 in.es in length.