overambitiousfrst

ive got a nasty old mk3 1.1 hcs fez and im having to put litre of oil in the engine everytime i fill it with petrol. i wanna fit another engine as its still got 6 months t+t. i cant find a decent mk3 hcs for a sensible price in essex so does anyone know if a 1.3 endura from a later fez/ka would be an easy swap? can i swap mounts, manifolds alternator etc and expect it to bolt straight in and work? any advice would be great. thanks.