Complex sentence: The TA was replaced by the TB Midget in May 1939 with the fitting of a smaller but more modern XPAG engine as fitted to the Morris Ten Series M but in a higher tuned state and like the TA with twin SU carburettors.
Split into simpler sentences: The TA was replaced by the TB Midget in May 1939. It had a smaller but more modern XPAG engine as fitted to the Morris Ten Series M, but in a more highly tuned state and like the TA with twin SU carburettors.