Converting your Jeep CJ7 from "single" exhaust system to a "dual" system will cause a smog check failure. It is not legal in California. The smog technician will consider the modification you've made an "emissions system tamper".
You must keep the original exhaust system configuration designed by Jeep for your Jeep's model (CJ7 with 304). On a side note... even when converting to a dual system and adding a second catalytic converter lowers emissions, the fact that the conversion is not factory will cause the vehicle to fail the smog inspection.
