What it is: a mechanical fuel-injected 4.5L cast-iron V8 from a 116 body:
1976-1980 450SE (Engine:117.986; Chassis:116.032;)
1976-1980 450SEL (Engine:117.986 4.5 V8; Chassis:116.033;)

What it is NOT:
280SE (Engine:117.984 4.5 V8; Chassis:108.067;)
280SEL (Engine:117.984 4.5 V8; Chassis:108.068;)
300SEL (Engine:117.981; Chassis:109.057;)
350SL (Engine:117.982; Chassis:107.043;)
350SL (Engine:117.982; Chassis:107.044;)
450SE (Engine:117.983; Chassis:116.032;)
450SEL (Engine:117.983; Chassis:116.033;)
450SL (Engine:117.982; Chassis:107.044;)
450SLC (Engine:117.982; Chassis:107.024;)
450SL (Engine:117.985; Chassis:107.044;)
450SLC (Engine:117.985; Chassis:107.024;)
500SEC (Engine:117.963; Chassis:126.044;)
500SEL (Engine:117.963; Chassis:126.037;)
560SEC (Engine:117.968; Chassis:126.045;)
560SEL (Engine:117.968; Chassis:126.039;)
560SL (Engine:117.967; Chassis:107.048;)