So I've had my 91 G2500 for 7 or 8 years now. In that time the 700R4 transmission burned up, and has been replaced by a 4L80E. To do this I repinned the PCM, harness, adding the transmission harness and swapped in an PCM from a 1994 G30. Also had to do some fabricating to make the transmission crossmember, shifter and driveshaft work. This has worked fine for going on 4 years now.

Last month towing my Jeep (Jeep plus trailer weigh in at right around 7000 pounds) over some Pennsylvania mountain passes I realize the TBI 350 is woefully underpowered to do this. It is fine in Ohio, and has been okay in the WV mountains (on I77, nothing steeper than a 5% grade. But it starts to complain at 10% grades, and 12% was pedal to the floor going 15mph.

As far as I can tell, the TBI 454 uses the same engine mounts, same bellhousing bolt pattern, and same computer. The only difference I believe is larger fuel injectors.

Is this swap really this simple? Or am I missing something.

On a sidenote, how does the engine come out? Disassemble the front of the van and out the front? Unbolt the crossmember and out the bottom?