Some of the write ups recommend not using MPI and a 4.0 head on a tired engine, I swapped on a 4.0 head and kept my carb and it made a big difference, There's nothing wrong with my engine I just don't feel the expense of doing the MPI conversion is justified at this time. I'm very happy with the 4.0 head and my motorcraft 2100 carb. <img src="/forums/images/graemlins/cheers.gif" alt="" />