I have a Hemi-6 carb system that I had trouble getting spark until I plugged a MAP sensor into the harness, even though the instructions say you don't need one. I had planned to run fixed timing in a drag race application. I pulled the MAP out of my '03 Dodge 5.7 and it plugged right in and had spark. I have a Drag-Pak intake that has provision for a MAP on the back of the intake. Found a Standard Motor Prod. MAP that bolts to intake. Don't remember the number, but could get it for you. Thoughts were, if you were to use this type of MAP, you could maybe drill and tap a 1" carb spacer for this type to run your MSD ignition and use the one in your FAST system for the injection, you could save from splicing harnesses. Depending on what type of intake you have...Just a thought...