* Computer Control: The 4L60E's control system is different between V6 and V8 applications. The V6 PCM (Powertrain Control Module) won't understand the signals from the V8-equipped transmission, and vice-versa. This means it won't shift correctly, if at all.
* Torque Converter: The torque converter from the V8 application is designed for higher torque and will likely not be compatible with the lower torque output of the V6 engine. It might even be physically too large.
* Input Shaft: There might be differences in the input shaft diameter and spline count to match the V6 engine's flexplate/flywheel.
* Wiring Harness: The wiring harness for the transmission will also need to be completely changed to accommodate the new transmission. This would be a major undertaking.
While some people might attempt adaptations, it's a complex and likely unsuccessful project unless you have significant transmission and automotive electrical experience. It would be far simpler and more reliable to find a used 4L60E transmission that's originally from a V6 Firebird or similar vehicle from the same year range.
