International C1100 front and rear turn signal bulbs both use 198 size bulbs for proper operation. The replacement chart covers 1963 to 1964 model years with corresponding bulb specifications.
The year-by-year compatibility chart below provides a quick reference to verify the correct bulb size for your vehicle.
The 198 bulb is the sole bulb type listed across all turn signal positions in the International C1100 specifications for 1963-1964.
The 198 bulb follows the ANSI standard, meaning it conforms to a standardized specification recognized across the United States and Canada.
It is a miniature wedge bulb, classified under the T5 designation, which refers to a tubular bulb with a wedge-style base that requires no separate socket retainer.
The 198 bulb operates at 12 volts and draws 2 watts, placing it at the low end of the power range for automotive signal lighting.
The Light Duty classification applies to both the front and rear turn signal positions for 1963-1964, indicating the 198 bulb is specified for lighter vehicle configurations within the C1100 lineup.
The same bulb size is shared between the front and rear turn signal positions across both listed model years, meaning the International C1100 uses a single bulb specification for all four turn signal locations.
The wedge base design of the 198 bulb is not interchangeable with bayonet or screw-base bulb types, even when voltage and wattage ratings may otherwise align.