The spark plug gap in your 1999 Chevrolet suburban is dependent upon the type of engine. The standard engine spark plug gap is .011.
A person must leave the right size gap for the spark plugs when changing them. The 1999 Chevy Suburban has a spark plug gap of .060 inches.
The spark plug gap for a 2004 Chevrolet Suburban should be set at .040 inches. The new spark plugs are pre-gapped and do not need adjusting.
Gap is .035
The corect gap is .035
0.035 in.
.035
set it a .0035
.045
0.035" gap
.35
5.7l & 7.4 = .60