HP Smart Coil Ignition Harness - 558-312 direct-fit The factory 1 piece line

The factory 1 piece line is nearly impossible to install unless you lift the cab off of the chassis

(Due to taller and wider engine dimensions)

please Contact Us about our Fitment Guide

7L V8 1988 - 1989 GMC C2500 350/5

HP Smart Coil Ignition Harness - 558-312 direct-fit The factory 1 piece lineOverview: HP Smart Coil ignition sub harness. Includes a pair of coil harnesses for an 8 cylinder engine. These harnesses are similar in design to factory GM LSx coil harnesses, but plug into Holley HP Smart Coils. They plug into Holley LSx plug and play main harnesses if one wants to replace factory LSx coils with Holley HP Smart Coils. If using a non LSx main harness, purchase PN 558 307 for connectors, wiring, terminals to connect directly to a