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ECU & Harnesses

ECU & Harnesses are the brains and wiring backbone of any EFI conversion. Whether standalone or piggyback, these units offer full control over fuel mapping, sensor inputs, and injector timing—vital for tuning modern engines.

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Holley HP EFI ECU & Harness Kit (HO550-603)
Holley HP EFI ECU & Harness Kit (HO550-603) HO550-603 Contact for availability
$5,292.10 - $5,292.10
$5,292.10
$5,292.10 - $5,292.10
$5,292.10
+ GST

Holley HP EFI ECU & Harness Kit (HO550-603)

Suit LS2/LS3/LS7 (58x Tooth Crank Sensor)

HP EFI ECU WITH HARNESSSuit LS2/LS3/LS7 (58x Tooth Crank Sensor)Part Number: HO550-603 Looking for a plug and playkit for your GM LS engine? TheHP...

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$5,292.10 - $5,292.10
$5,292.10
$5,292.10 - $5,292.10
$5,292.10
+ GST
Contact for availability
Holley Dominator EFI Auxiliary Harness (HO558-403) HO558-403
$424.00 - $424.00
$424.00
$424.00 - $424.00
$424.00
+ GST

Holley Dominator EFI Auxiliary Harness (HO558-403)

J3 ECU Connector

DOMINATOR EFI J3 P3 AUXILIARYJ3 ECU ConnectorPart Number: HO558-403 17 User Programmable Inputs and Outputs

$424.00 - $424.00
$424.00
$424.00 - $424.00
$424.00
+ GST
Holley Terminator X Max ECU Kit, 92-97 4R70W Transmission - EV1 Injectors (HO550-943)
$4,233.50 - $4,233.50
$4,233.50
$4,233.50 - $4,233.50
$4,233.50
+ GST

Holley Terminator X Max ECU Kit, 92-97 4R70W Transmission - EV1 Injectors (HO550-943)

Suit Ford MPFI

TERMINATOR X MAX ECU KITSuit Ford MPFIPart Number: HO550-943 Take control of your conventional Ford engine with Terminator X! Don't settle fora fa...

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$4,233.50 - $4,233.50
$4,233.50
$4,233.50 - $4,233.50
$4,233.50
+ GST
Holley Terminator X Max ECU Kit, 24x Crank - 1x Cam - EV1 Injectors (HO550-916) Contact for availability
$4,630.40 - $4,630.40
$4,630.40
$4,630.40 - $4,630.40
$4,630.40
+ GST

Holley Terminator X Max ECU Kit, 24x Crank - 1x Cam - EV1 Injectors (HO550-916)

Suit GM LS1/LS6

HO550-916 - TERMINATOR X MAX ECU KIT, LS1Suit GM LS1/LS6Part Number: HO550-916Take control of your LS engine with Terminator X Max! Don't settle fo...

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$4,630.40 - $4,630.40
$4,630.40
$4,630.40 - $4,630.40
$4,630.40
+ GST
Contact for availability
MSD Atomic Replacement Hand Controller Module (MSD2912) MSD2912
Contact for availability
$726.00 - $726.00
$726.00
$726.00 - $726.00
$726.00
+ GST

MSD Atomic Replacement Hand Controller Module (MSD2912)

Suit MSD2900 & MSD2910 Atomic TBI EFI Kits

REPLACEMENT HAND CONTROLLERSuit MSD2900 & MSD2910 Atomic TBI EFI KitsPart Number: MSD2912 The Atomic’s handheld monitor gives you access to ...

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$726.00 - $726.00
$726.00
$726.00 - $726.00
$726.00
+ GST
Contact for availability
Holley Auxiliary Harness - J2B Connector (HO558-402) HO558-402
Contact for availability
$246.50 - $246.50
$246.50
$246.50 - $246.50
$246.50
+ GST

Holley Auxiliary Harness - J2B Connector (HO558-402)

Suit Dominator EFI

HO558-402 - J2B P2B ECU EFI DOMINATORSuit Dominator EFIPart Number: HO558-402HARNESS KIT INCLUDES: Loose wires with pre-crimped ECU pins for the fo...

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$246.50 - $246.50
$246.50
$246.50 - $246.50
$246.50
+ GST
Contact for availability
Holley Auxiliary Harness - J2A Connector (HO558-401) HO558-401
Contact for availability
$333.20 - $333.20
$333.20
$333.20 - $333.20
$333.20
+ GST

Holley Auxiliary Harness - J2A Connector (HO558-401)

Suit Dominator EFI

HO558-401 - P2A J2A EFI DOMINATOR AUXSuit Dominator EFIPart Number: HO558-401HARNESS KIT INCLUDES: J2A ECU Connector#2 Wide band oxygen sensor harn...

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$333.20 - $333.20
$333.20
$333.20 - $333.20
$333.20
+ GST
Contact for availability
Holley GPS Digital Dash USB Module (HO554-140)
Holley GPS Digital Dash USB Module (HO554-140) HO554-140
$227.80 - $227.80
$227.80
$227.80 - $227.80
$227.80
+ GST

Holley GPS Digital Dash USB Module (HO554-140)

Suit HO553-109 & HO553-106 Digital Dash

GPS DIGITAL DASH USB MODULESuit HO553-109 & HO553-106 Digital DashPart Number: HO554-140 Have you been searching fora reason to discard your o...

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$227.80 - $227.80
$227.80
$227.80 - $227.80
$227.80
+ GST
Holley EFI 12.3" Pro Dash (HO553-111)
Holley EFI 12.3" Pro Dash (HO553-111) HO553-111
$5,445.60 - $5,445.60
$5,445.60
$5,445.60 - $5,445.60
$5,445.60
+ GST

Holley EFI 12.3" Pro Dash (HO553-111)

Digital Touch Screen

HOLLEY EFI 12.3" PRO DASHDigital Touch ScreenPart Number: HO553-111 Trust. Whether it's your engine builder, team members, or EFI System, trust is...

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$5,445.60 - $5,445.60
$5,445.60
$5,445.60 - $5,445.60
$5,445.60
+ GST
Holley 3.5" LCD Touch Screen (HO553-108)
Holley 3.5" LCD Touch Screen (HO553-108) HO553-108
$879.20 - $879.20
$879.20
$879.20 - $879.20
$879.20
+ GST

Holley 3.5" LCD Touch Screen (HO553-108)

Suit Holley EFI

HOLLEY EFI 3.5" TOUCH LCD SCRNSuit Holley EFIPart Number: HO553-108 The touch screen LCD provides a dynamic range of tuning and data monitoring op...

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$879.20 - $879.20
$879.20
$879.20 - $879.20
$879.20
+ GST