I had similiar driveability issues after making cam and head mods to my car. Although mine is naturally aspirated. The only way I could correct the bucking and surging was to burn a custom chip. Once that was done these problems went away and I picked up a little more HP to boot.
I did not notice the rear gear ratio you are running...but a higher ratio gear also improves the streetability just because you spend less time in that 1500-2500 range.
Not sure if I helped but there's my experience.
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fordgasm
CLICK HERE to see my 87 GT