The bell housing is removeable in that in unbolts, but the backside where it attaches to the trans is also the vlv control circuit for part of the overdrive assy where the oil pump goes thru the part you are talking about , it is not removable as a bellhousing in the true since of the word, that you could just bolt on another bell, but it should bolt to the olds eng as it uses the small bolt circle of the 60 degree eng, all isuzu v6 engs use 2 bolt circles both are the 60 degree design , the inner circle is for the automatics and the outer circle is for the manual shift , just have to watch for the dowel pin location,Jerry