[Tim Brewer]

I'm not sure about what your Summit starter really is,(i'm sure it's rebadged) but I had basically the same problem with my 1st mini starter. As I recall, for some reason, one particular starter was said to fit our (I have basically the same setup as you), application, but it was for an older Lakewood bell which seemed to change somewhere along the way without notice. It took a lot of calling, but ended up being a Powermaster XS Torque mini starter, part # pwm 9505. No problems, no shims or grinding. If your shims work, cool, but Fords really shouldn't need shims with the correct starter. The Powermaster starter is $217.00 and bolts right up.
Tim