ACDelco Spark Plug RBL12 5612646

Description:

🔧 Part Overview - DUSTY SHELF WARE BUT GOOD CONDITION

• ACDelco Part Number: RBL12

• GM Part Number: 5612646 (commonly associated with RBL12 in GM catalogs)

• Type: Resistor copper spark plug

• Thread Size: 14mm x 1.25mm

• Seat Type: Gasket

• Reach: Approx. 19mm (0.75")

• Hex Size: 13/16"

• Terminal: Fixed

• Electrode Material: Copper core with nickel alloy ground electrode

• Country of Origin: Typically marked “Made in USA”

🚗 Specific Applications

The RBL12 plug was commonly used in:

• 1970s–1980s GM vehicles including Chevrolet, Pontiac, Oldsmobile, Buick, and Cadillac

• Small-block and big-block V8 engines (305, 350, 400, 454 CI)

• Marine engines (MerCruiser, OMC, Volvo Penta)

• Industrial and agricultural engines

• Classic hot rods and performance builds using 14mm gasketed heads