The spectroscopic and kinetic consequences associated with the strong homogeneous interactions between (i) CO(b (3)Sigma(+),v'=0) and CO(a' (3)Sigma(+), v'=30, 31, and 32), (ii) CO(b (3)Sigma(+),v'=1) and CO(a' (3)Sigma(+), v'=34, 35, and 36), (iii) CO(b (3)Sigma(+),v'=2) and CO(a' (3)Sigma(+), v'=40 and 41) levels are evaluated. Mixing of b (3)Sigma(+) character into the a' (3)Sigma(+) levels reduces the radiative lifetimes of the latter, because the lifetimes of pure b (3)Sigma(+) and a' (3)Sigma(+) states are approximately 50 ns and 3 mu s, respectively. The strength of the interaction changes with rotational level, and the rotational line intensities and the radiative branching to different v " levels of the CO(a' (3)Sigma(+)-a (3)Pi) transition are strongly affected. Comparison of high resolution CO(a', v'=31, 34, and 35) experimental spectra with calculated spectra shows a marked underestimation of the rotational temperature of these CO(a',v') levels unless the mixing is explicitly recognized. With benefit of this knowledge, some results from the Kr(5s'[1/2](0))+CO excitation-transfer reaction need to be reinterpreted. Emission spectra for 300 K rotational distributions from CO(b,v'=0, 1, and 2) and CO(a',v'=30, 31, 34, and 35) were used to obtain vibrational band intensities for comparison with model calculations. Analysis of the pressure and time dependence of the laser-induced fluorescence data permit the electronic relaxation mechanism of the CO(b,v'=0, 1, 2) and CO(a',v'=31 and 35) levels in He buffer gas to be discussed. The experimental radiative lifetimes of CO(b,v'=0,1,2) were measured as 60 +/- 6, 63 +/- 4, and 58 +/-4 ns, respectively. The role of the homogeneously perturbed levels in the collisional relaxation mechanism is discussed.