My TH350 tranny is shifting late 1st to 2nd and 2nd to 3rd. I developed this problem after changing my engine from a mild 350 to a stroked 383. My tranny is about 2 yrs old and this problrm didn't exist prior to changing engine. My engine is generaing significant RPM before the tranny is changing gears. What I have beed told locaaly is it's either the modulator or kickdown cable. What I'm having trouble with is it was shifting fine before the engine rebuild. I removed the kickdown cable (detent) and I still had the problem. Do you think I need to adjust this cable?? If so how? what else do you suggest?