Did you get your timing problem resolved? With the Fitech timing control, get a helper and have them hold the rpm at 2200 ish rpm. It will help to stabilize the timing off of idle. Have your helper read the timing from the handheld and compare it to what you are reading on your timing light. For example you had said your handheld said 18 while your timing light read 13. In that case, you would rotate your distributor until both your handheld and your timing light indicated 18 degrees. That should help to get your timing synced up, because in that previous example you would be about 5 degrees lower everywhere in your map. I'm not sure if you set your adjustable rotor up as in the Fitech instructions or phased it with another cap with a hole in it. When I phased mine in correctly, it was different than what Fitech stated in their instructions. As you play with the Fitech more, it may make sense to alter some of the breakpoint settings to more accurately set where all of your timing advance comes in and what MAP setting you do most of your cruising at. I'm not a Fitech expert but am running a 600 power adder version on a 428, so have learned a few things over the last couple of years. Let me know if there is anything I can help with.
