Tailhousings / gearboxes are the same length, ke30 ones just appear to be shorter due shifter position is further forward.
That means you can use your old driveshaft with it.
If you already have a 5speed in your ke70 you can just switch the tailhousing with shifters over.
If not, you will need tailhousing with shifter from a ke70
unless you want to cut a shifterhole 10cm further forward