You're both partially right. Technically its a 700R4, but from what my tranny shop tells me there really is no difference between it and a 4l60.

As for the swap, there's really no way to bolt the 4.3 to either of the trannys isuzu uses in the 3.2 equipped trucks, except maybe with that ultra rare impossible to find adapter. To tell the truth I'm not sure why you would swap a 3.2 for a 4.3. The chevy has a bit more torque, but thats about it. If I had it to do over again I'd drop in a 3.2 with a 60* bolt patern 700R4 and the same Dana 300. The 3.2 is a really nice motor, and so is the 4.3, but I really dont see enough benefits to one or the other to go through the time and expense of swapping one for the other.

Dallas