Wrong bellhousing is one problem, flywheel & clutch are another. The V8 parts are bigger than the 4-cyl & 6-cyl parts. Also, the v8 trannys have beefed up bearings.
You can probably use the 4-cyl parts on a comparable 6 w/o trouble. Somewhere around there, they changed the tranny-engine mounting to be on a slant. Eyeball the parts.