I just did the 175-HP kit in my 91...couldnt be happier. Shifts are nearly instant, upshifts and downshifts are great. Had to drill out relief holes in the valve plates, and used the black spring.
If you are stalling, you may have left out an aurum ball or one of your springs is binding...i would recheck your install for errors. Otherwise, look elsewhere for your issues (the torque converter comes to mind) check your fluid and filter as well.