....on a 350 my understanding has always been that the detent cable basically does nothing unless you got to FULL throttle...like passing gear.
....If you have a shift kit in, you should be getting your neck snapped a little..or maybe it depends on the shift kit. I'm taking mine back out of my 37. I hate the tires "chirping" every time it shifts and tired of my neck popping. I have to soft foot it to get going. JUST FYI