I now have a selection of 4 speed boxes so i can make a reasonably good one, is there a way i can remove the tail housing without taking all the gears with it? of the 5 boxes one has a different size thread for the gearshift although the same casting no's. it looks like a later box but is the best of the bunch, thanks

What type of boxes do you have???

They are all standard mk2 1300 crosflow boxes