Why can't the engine be removed independently of the transmission?
It can, if you're willing to do a lot of extra work. Since there are bolts holding the bellhousing to the block on a 235 that are buried behind the flywheel, you would need to remove the transmission, clutch, and flywheel anyway, unbolt the bellhousing from the block, and leave the bellhousing attached to the crossmember while you pull the engine.
If you're willing to do that, go ahead.
Jerry