  Based on available experimental data, a new set of Nilsson parameters is
proposed for proton-rich nuclei with proton or neutron numbers $28\leq N\leq
40$. The resulting single-particle spectra are compared with those from
relativistic and non-relativistic mean field theories. Collective excitations
in some even--even proton-rich nuclei in the upper $pf$ shell are investigated
using the Projected Shell Model with the new Nilsson basis. It is found that
the regular bands are sharply disturbed by band crossings involving $1g_{9/2}$
neutrons and protons. Physical quantities for exploring the nature of the band
disturbance and the role of the $1g_{9/2}$ single-particle are predicted, which
may be tested by new experiments with radioactive beams.
