theyre pre gapped otherwise it depends on engine specification
0.035 plug gap
18436572
should be .035
The diagram.
.035 gap standard and stock
The spark plug gap for a 1991 Chevy Silverado 2500 V8-350 is .035, according to major spark plug manufacturers (i.e. Autolite, Bosch, Denso, NGK).
0.035"
0.45 inch
4.3? Follow the spark plug wires from the spark plugs, they will lead you right to the distributor.
.035
The 1991 Mercury Marquis spark plug gap is .034. Most spark plugs will be pre-gapped by the spark plug manufacturer.
Spark plug gap chevy ls blazer