I believe the bellhousing will swap over. I doubt that the three speed will stand up to the warmed over 350 for very long; however, a 4 speed Muncie or a T-10 out of a first generation Camaro or Firebird, or a Chevelle or other mid-size, or a three speed from a Firebird will bolt right up to the bellhousing, and should be the same length as the three speed you have, and same output shaft splines. An easy swap.