recalibrating kickdown point on a TH 350

[DAWG]

since ive changed my rear from 3:08 to 3:73 the kickdown has been acting funny.
Itll kickdown for 2 to 3 seconds then back?
with the 3:08 it would hold it until I let off the gas.
Im assuming that the modulator would need an adjustment.
also id like to move the downshift up some
example : it would not go into kickdown over 55 mph
anything under 55 it would kick down
id like to move the limit up to 65 if possible
maybe a govenor spring or weight adjustment?
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