<h2 style="font-size: clamp(18px, 3vw, 21px); margin-bottom: 15px; line-height: 1.3;">High-Output Ignition Coil and Spark Plug Kit for 1996-1999 GMC C/K Trucks 4.3L, 5.0L, 5.7L (GMT400 / Vortec)</h2> <p><strong>What it Does:</strong> The direct-fit Ignition Coil and Spark Plug Kit restores primary and secondary ignition circuit saturation on 1996-1999 GMC C/K Trucks to eliminate misfires, rough idle, and spark blowout under load.</p> <h3>The Stock GMC C/K Trucks Ignition Saturation Breakdown</h3> <p>Factory ignition setups on the <strong>GMT400</strong> platform are notorious for coil heat saturation. Mounted adjacent to the intake manifold, the factory coil casing endures severe thermal cycling that degrades its internal resin windings. Over time, internal micro-arcing weakens spark output below the threshold required to jump worn spark plug gaps under heavy load. Concurrently, factory plugs suffer center-electrode erosion, increasing resistance and overworking the secondary circuit. This thermal decay leads to stumbling off-idle, intermittent P0300 multi-cylinder misfires, unburned fuel entering the catalytic converter, and loss of towing power on <strong>Vortec L35</strong>, <strong>L30</strong>, and <strong>L31</strong> platforms.</p> <h3>The Engineering Solution</h3> <p>This replacement kit resolves thermal breakdown by utilizing high-dielectric epoxy encapsulation within the coil core, effectively isolating the primary and secondary copper windings against heat soak and dielectric puncture. Paired with fresh matched spark plugs engineered for uniform spark kernel propagation, the system maintains consistent arc voltage across the RPM band. Designed to mount directly to the factory bracket without wiring modifications, this kit stabilizes dwell times and ensures complete flame-front propagation inside the combustion chamber.</p> <h3>Technical Specifications</h3> <div style="overflow-x: auto; margin-bottom: 20px;"> <table width="100%" style="border-collapse: collapse; border: 1px solid #e0e0e0; font-size: 14px; min-width: 300px;"> <tr style="background-color: #f9f9f9;"> <th style="padding:10px; text-align: left; border: 1px solid #e0e0e0;">Fitment</th> <td style="padding:10px; border: 1px solid #e0e0e0;">1996-1999 GMC C/K Trucks (C1500 / K1500)</td> </tr> <tr> <th style="padding:10px; text-align: left; border: 1px solid #e0e0e0;">Engine / Chassis</th> <td style="padding:10px; border: 1px solid #e0e0e0;">4.3L V6 (L35), 5.0L V8 (L30), 5.7L V8 (L31) / <strong>GMT400</strong> </td> </tr> <tr style="background-color: #f9f9f9;"> <th style="padding:10px; text-align: left; border: 1px solid #e0e0e0;">Stock Output</th> <td style="padding:10px; border: 1px solid #e0e0e0;">200–255 hp / 255–335 lb-ft</td> </tr> <tr> <th style="padding:10px; text-align: left; border: 1px solid #e0e0e0;">Replaces OEM Part #</th> <td style="padding:10px; border: 1px solid #e0e0e0;"> <strong>10489421</strong>, <strong>19207138</strong>, <strong>19418996</strong>, <strong>D577</strong>, <strong>DR49</strong> </td> </tr> </table> </div> <h3>Compatibility</h3> <ul> <li>1996-1998 GMC C1500 4.3L</li> <li>1996-1999 GMC C1500 5.0L, 5.7L</li> <li>1996-1998 GMC K1500 4.3L</li> <li>1996-1999 GMC K1500 5.0L, 5.7L</li> </ul> <h3>Frequently Asked Questions</h3> <p><strong>Does this fit the GMT400 C/K Trucks?</strong><br> Yes, this is a direct fit for the 1996-1999 GMC C/K Trucks equipped with the Vortec 4.3L, 5.0L, or 5.7L engines.</p> <p><strong>Why are eight spark plugs included if my truck is a 4.3L V6?</strong><br> The kit includes 8 plugs to cover all small-block V8 configurations; 4.3L V6 models use 6 plugs, leaving two as spares.</p> <h3>The GMC Heavy-Duty Caliber</h3> <p>Built to handle severe commercial duty and continuous trailering, this ignition overhaul ensures high-load spark stability in all weather conditions.</p>