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Thread: CNP extra harnesses required?

  1. #1
    Join Date
    May 2021
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    Default CNP extra harnesses required?

    What harnesses are required to do Coil-Near-Plug and be successful without any hiccups? Terminator X Fox body harness, getting a Dual Sync distributor. My understanding is that I need 558-307 and then either the factory LSx sub-coil harnesses or 558-312 and the coils. Is this correct or is there more to it?
    Last edited by Super92notcH; 05-04-2021 at 04:50 PM.

  2. #2
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    Dec 2009
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    Default

    Originally Posted by Danny Cabral
    If you already have or you're purchasing a new Holley EFI non-LSx main harness:
    The Holley 558-307 CNP main harness is for Holley's Coil-On-Plug smart coils and LSx ignition coils (nine terminated loose wires into J1B).
    If using Holley's 556-112 CNP coils, the Holley 558-318 CNP coil sub-harness is also required (or the Holley 556-128 CNP Big Wire V8 Kit).
    For LSx coils, Holley 558-307 CNP main harness plugs into two GM 12579355 CNP sub-harnesses or Holley 558-321 LSx coil sub-harnesses.
    If you had a Holley EFI LSx main harness, you wouldn't need the Holley 558-307 CNP main harness or the 558-318 CNP coil sub-harness.
    https://www.holley.com/products/igni...nd_components/ (Holley EFI Coil-Near-Plug Ignition Components)
    https://www.holley.com/products/igni.../parts/556-128 (Holley EFI 556-128 Coil-Near-Plug Big Wire V8 Kit)
    https://www.holley.com/products/fuel.../parts/558-117 (Holley EFI 558-117 Universal MPFI Coil-Near-Plug Main Harness)
    https://www.holley.com/products/fuel.../parts/558-118 (Holley EFI 558-118 Ford Universal MPFI Coil-Near-Plug Main Harness)
    https://forums.holley.com/showthread...3038#post33038 (Detailed Crank Trigger & CNP/DIS Conversion Information & Reasoning)
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Holley Dominator MPFI & DIS, 36-1 crank trigger, 1x cam sync, 200A 3G alternator, Optima Red battery, R134a A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans, Frostbite 3-core aluminum radiator, Pypes dual 2.5" exhaust, off-road X-pipe, shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, BMR upper & lower torque box reinforcements, LenTech Strip Terminator wide-ratio AOD, 3000 RPM converter, B&M Hammer shifter, Stifflers trans crossmember & driveshaft safety loop, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

  3. #3
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    Default

    So 558-118 would plug into the Terminator X, and then use 556-128 because I'd just use the Big Wire Kit?

  4. #4
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    The Holley Terminator X Main Harnesses (& Unterminated Harness) are the same as the HP & Dominator EFI systems. Also, the Terminator X & X Max ECUs are sold separately (LINK). And yes, use the Holley 556-128 CNP Big Wire V8 Kit, as opposed to the Holley 558-312 CNP Coil Harness Kit.
    May God's grace bless you in the Lord Jesus Christ.
    '92 Ford Mustang GT: 385" SBF, Dart SHP 8.2 block, TFS T/W 11R 205 heads, 232°-244° duration/.623" lift/114° LSA camshaft, 12:1 C/R, TFS R-Series FTI ported intake, BBK 80mm T/B, Holley Dominator MPFI & DIS, 36-1 crank trigger, 1x cam sync, 200A 3G alternator, Optima Red battery, R134a A/C, 100HP progressive dry direct-port NOS, Spal dual 12" fans, Frostbite 3-core aluminum radiator, Pypes dual 2.5" exhaust, off-road X-pipe, shorty headers, -6AN fuel system plumbing, Walbro 255 LPH pump, S&W subframe connectors, BMR upper & lower torque box reinforcements, LenTech Strip Terminator wide-ratio AOD, 3000 RPM converter, B&M Hammer shifter, Stifflers trans crossmember & driveshaft safety loop, FPP aluminum driveshaft, FPP 3.31 gears, Cobra Trac-Lok differential, Moser 31 spline axles, '04 Cobra 4-disc brakes, '93 Cobra booster & M/C, 5-lug Bullitt wheels & 245/45R17 M/T Street Comp tires.

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