call ckperformance about the 4l60e an see what they have about those problems, i would think they might have some of those issues solved i agree with the reliability of a properly built 350,mine is over 17 years old and still shifts hard behind my 430 that im sure is in the 400 hp range my 350 has been in 2 different cars,been behind 5 different engines and is still going strong,some leaks but will get to those