We report on resonant Raman experiments carried out on wurtzite InAs nanowires. Resonant conditions have been obtained by tuning either the excitation energy or the band gap through external high pressure at fixed excitation energy. A complete azimuthal study of the Raman spectra with two laser excitation lines (2.41 and 1.92 eV) has also been performed on a single wire. The measured E-2(H) mode resonance indicates that the E-1(A) gap is about 2.4 eV, which is considerably reduced with respect to the zinc-blende InAs E-1 gap. These findings confirm recent theoretical calculations of crystal phase induced bandstructure modifications.