I think this says it all:
*Mobil 1 Truck & SUV
SAE Grade 5W-40
Viscosity, ASTM D 445
cSt @ 40ºC 102
cSt @ 100ºC 14. 8
Viscosity Index, ASTM D 2270 151
Sulfated Ash, wt%, ASTM D 874 1. 35
Total Base #, mg KOH/g, ASTM D 2896 12
Pour Point, ºC, ASTM D 97 -45
Flash Point, ºC, ASTM D 92 226
Density @ 15ºC kg/l, ASTM D 4052 0. 854
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*Mobil Delvac 1 5W-40
SAE Grade 5W-40
Viscosity, ASTM D 445
cSt @ 40ºC 102
cSt @ 100ºC 14. 8
Viscosity Index, ASTM D 2270 151
Sulfated Ash, wt%, ASTM D 874 1. 35
Total Base #, mg KOH/g, ASTM D 2896 12
Pour Point, ºC, ASTM D 97 -45
Flash Point, ºC, ASTM D 92 226
Density @ 15ºC kg/l, ASTM D 4052 0. 854
It's the same stuff!