  We present Southern African Large Telescope (SALT) follow-up observations of
seven massive clusters detected by the Atacama Cosmology Telescope (ACT) on the
celestial equator using the Sunyaev-Zel'dovich (SZ) effect. We conducted
multi-object spectroscopic observations with the Robert Stobie Spectrograph in
order to measure galaxy redshifts in each cluster field, determine the cluster
line-of-sight velocity dispersions, and infer the cluster dynamical masses. We
find that the clusters, which span the redshift range 0.3 < z < 0.55, range in
mass from (5 -- 20) x 10$^{14}$ solar masses (M200c). Their masses, given their
SZ signals, are similar to those of southern hemisphere ACT clusters previously
observed using Gemini and the VLT. We note that the brightest cluster galaxy in
one of the systems studied, ACT-CL J0320.4+0032 at z = 0.38, hosts a Type II
quasar. Only a handful of such systems are currently known, and therefore
ACT-CL J0320.4+0032 may be a rare example of a very massive halo in which
quasar-mode feedback is actively taking place.
