The two experiments, BaBar (PEP-II) and E-158, require quite different beams in the linac at the Stanford Linear Accelerator Center, SLAC. The first needs damped beams from the damping rings and low energies at the extraction points from the main linac. For E-158, an undamped, polarized beam bypasses the damping rings, and gets accelerated to energies of 45.6 and 48.7 GeV with 14% or 8% beam loading, resulting in beam charges of 6.5{center_dot}10{sup 11} and 4.0{center_dot}10{sup 11} particles. The linac betatron lattice must accommodate energy differences of up to 50%, 9 to 14 GeV at the one-third point in the linac. Gradually decreasing cell phase advance from about 100 degrees to 60 degrees near the PEP-II extraction points in the linac reduces the chromatic betatron mismatch of the PEP-II beams to an acceptable level. Additionally, pulsed correctors for steering and a pulsed RF phase shifter were installed to have more independent control for the different beams. Two new feedback systems have been implemented, which (a) stabilize the trajectory at the end of the linac, and (b) dithers the pulsed RF phase shifter to stabilize the beam phase with respect to the accelerator RF crest. A reduced intensity jitter from themore » gun and a skew quadrupole after the linac, which mixes the blown-up, stable x-emittance with the varying y-spot also stabilized the beam conditions on the fixed target.« less