My buddy just took off his loud mouth and I was wonderiing if it would fit my camaro 87 if I cut the passenger side tailpipe to narrow it. I will be using Hooker tips most likely. I will have to make a pipe from y to axle pipe though.

 

The only differences between the 3rd and 4th gen exhaust systems are the hanger type/location and the connection to the y-pipe.

 

exactly...the I-pipe on the LS1 exhaust will end in the center of the car, next to the driveshaft and torque arm. while the end of the Ypipe for the 3rd gen ends on the passenger side of the car.

SLP use to make the "S" pipe that would allow the conversion. but i would think any good muffler shop could do it. but i would buy some 90* bends to take with you, most shops don't do mandrel bends.