i recently swapped my 2-speed with a th350. we had an issue with it not shifting out of first. turns out, the problem was the original modulator tube was too small to hold enough vaccuum for the th350. we swapped it out with a larger one and now it shifts perfectly!! so just for future reference...in a 65 cutlass w/ a 330ci, you will need to change out the original modulator tube with a larger one to accomodate the 3-speed. hope this helps someone in the future, cuz i was going crazy!!