The intrinsic viscosity [eta] was determined for 23 samples of atactic oligo- and poly(alpha-methylstyrene)s (a-PalphaMS), each with the fraction of racemic diads f(r) = 0.72, in the range of weight-average molecular weight M-w from 4.12 x 10(2) to 5.46 x 10(6) in three good solvents, toluene, 4-tert-butyltoluene, and n-butyl chloride, at 25.0 degreesC. The translational diffusion coefficient D was also determined from dynamic light-scattering measurements for 17 a-PalphaMS samples in the range of M-w from 1.04 x 10(3) to 3.22 x 10(6) under the same solvent conditions. It was found that the values of [eta] in toluene and n-butyl chloride are appreciably smaller than the previous ones of [eta](Theta) in cyclohexane at 30.5 degreesC (Theta) in the oligomer region in which the intramolecular excluded-volume effect may be ignored, while those of [eta] in 4-tert-butyltoluene are only slightly larger than the latter there because of the dependence on solvent of the hydrodynamic chain (bead) diameter. The disagreement in toluene and n-butyl chloride may be regarded as arising from the so-called specific interaction between polymer and solvent molecules, and therefore the viscosity-radius expansion factor alpha(eta) in these solvents was calculated after removing its contribution. On the other hand, the values of the hydrodynamic radius R-H defined from D in the three good solvents were found to agree well with the previous ones of R-H,R-Theta in cyclohexane at Theta in the oligomer region, and therefore the hydrodynamic-radius expansion factor alpha(H) could be calculated straightforwardly. It was then found that both plots of alpha(eta) and alpha(H) against the scaled excluded-volume parameter (z) over tilde for a-PalphaMS in the three good solvents along with those for atactic polystyrene and atactic and isotactic poly(methyl methacrylate)s previously studied form their respective single-composite curves, confirming the validity of the quasi-two-parameter scheme that all expansion factors are functions only of 2 irrespective of the differences in polymer species (chain stiffness and local chain conformation) and solvent condition.