a catalytic converter adapted for use in the exhaust system of internal combustion engines comprising a shell made of a pair of half shells forming an inlet chamber and a catalyst chamber , and a funnel - like outlet shell forming an outlet chamber . the inlet chamber has inlet ports communicating with exhaust pipes respectively and the outlet chamber has an outlet port communicating with a downstream exhaust pipe . the catalyst chamber resiliently supports a monolithic type catalyst element . the outlet shell which defines the outlet chamber is adapted to engage the inside of the pair of shells which form the catalyst chamber .