You can put the later engine in, but will need to make new upper floorboards to account for the pedals shifting over some - they had a different spacing but all the floor plates are available from the vendors.
One friend also went so far as to weld diamond pedal heads onto the later pedals to make it look more correct but I prefer the wider pedals - I'm not sure if the earlier pedals will work in the hogshead, but I'm sure someone else will know.
Good luck