The L03 is the throttle-body-injected 305 — a single throttle-body unit feeding a wet-flow intake plenum, replacing the Quadrajet of the LG4. Less elaborate than the LB9 TPI but markedly easier to maintain and certify. By 1990 it made 170 hp net at 4,400 rpm and 255 lb-ft at 2,400 rpm, paired with either the 700-R4 automatic or the T-5 manual.
Plenum cross-references L03 against VIN 8th char E. On cars where the SPID engine line and the VIN engine character disagree, the conflict is surfaced rather than silently resolved.