Steve,
I had trouble with my EFI and took another approach. I have the 351 Windsor(now 408) with the AFR 205 heads. I wanted to retain my EFI. I was using the FAST XFI and XIM boxes. When I had my trouble it was suggested that I keep the FAST setup and go with the MSD box and distributor. What I did was outlined by the people at MSD. I kept the crank trigger for the FAST box. It tells the Fast system that TDC will occur in 50 degrees of rotation. That is how it sets the timing. I added the MSD 6A box(now wish I had gotten the 6AL box for the rev limiters). The box then fires when the FAST tells it to fire. Next added the MSD distributor and did away with all the springs and locked out the distributor(no advance). Now the 6A is controlled with the FAST box for timing. The distributor just routes the spark to the right plug and has to be setup or "phased in". An extra distributor cover is needed and a hole is drilled just over the #1 cylinder position. Then the engine is started and you set the distributor so that at full advance, at about 3000 RPMs, the arc of spark is set so that it won't jump to the next plug. You will see the arc at one edge of the #1 plug lead at start, and when advanced it will be at the other end of the lead. Mine runs flawlessly. As I mentioned the step by step is outlined by MSD on the side of their box the distributor comes in. They may have a video of it on their web site. It is an easy transition as I did it by myself with no assistance. Will work great if you want to retain the EFI.
Bill
