4 speed trans swap question?

yeah after I posted I realized what I had asked. its a small block bellhousing for a 3spd. and he wants the big block 4spd trans I have to put in his a-body will it fit

What is the trans out of and what year is the trans ? 18 spline or 23 spline ? the bearing retainer may be the wrong size depending on the year of the trans but that can be worked around .

Does his bellhousing have both 3 and 4 speed patterns ? If not he is going to need to get another bellhousing.