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Free EFI Conversion Guide
Holley Sniper EFI System Selector
Find the right Sniper EFI throttle body kit for your engine in three steps. Select your carburettor flange pattern, target power level and kit type - we'll match you to the exact Holley Sniper EFI system and show you every part you need, with direct links to add to basket.
Carb Flange Matching
Every Sniper EFI system is built around a specific carburettor bolt pattern. We identify the right flange for your intake so the throttle body bolts straight on - no adaptors, no drilling.
Power Level Sizing
Injector capacity and ECU mapping vary by kit. We size the system to your target horsepower so you're not running near the limit - or paying for headroom you'll never use.
Complete Parts List
Base kits need a fuel pump and plumbing to work. Master kits include everything. We show you the full required parts list with prices and direct links - nothing hidden, nothing missed.
Holley Sniper EFI UK - Find the Right Throttle Body Conversion Kit
The Holley Sniper EFI range is the most popular carburettor-replacement EFI system available, and Billy's Speed Shop is an authorised UK distributor with stock in both UK and US warehouses. All prices shown include VAT and import duties - no hidden fees.
The single most common mistake in a Sniper EFI conversion is selecting the wrong flange pattern. The range covers eight different carburettor bolt patterns - from the ubiquitous Holley 4150 square bore through to the Quadrajet spread bore, Dominator 4500, Rochester 2GC, Carter BBD Jeep and the Autolite 1100 Ford pattern. Fit the wrong one and the throttle body simply won't bolt on.
This selector takes the guesswork out completely. Three questions, one result - with every part you'll need listed, priced and linked directly to the Billy's shop.
What the Sniper EFI Selector Covers
- All eight Sniper EFI carburettor flange patterns
- Power level matching - from 200hp to 1,375hp
- Base, Master and Stealth kit options explained
- Required supporting parts - pump, filters, hose, fittings
- Recommended add-ons - sealing plate, HyperSpark ignition
- Direct links to every item in the Billy's shop
- Running total of required items before you checkout
Ready to find your system?
01
Select Your Flange
Choose the carburettor bolt pattern on your intake manifold. Eight options - not sure? We can measure it free in-store.
02
Set Your Power Level
Pick your target horsepower. Options vary by flange. Single-application flanges skip this step automatically.
03
Choose Kit Type
Base (you supply fuel system), Master (fuel system included), or Stealth (carb-look housing). One-option paths skip this step too.
04
Order Direct
Your matched system with a complete parts list, prices and Add to Basket links straight to the Billy's shop.
Sniper EFI System Selector
Select your options below - the selector advances automatically when only one choice exists.
1
Flange
2
Power
3
Kit Type
4
Your Kit
The bolt pattern on top of your intake manifold where the carburettor or throttle body sits. Match the diagram to your manifold opening.
Holley 4150
Square Bore
Square Bore
Most popular. Fits virtually all Holley, Edelbrock & aftermarket intakes. Up to 1,375hp.
Most Common
Holley 4500
Dominator
Dominator
Larger 4-barrel for big-power builds. Race intakes and high-flow aftermarket manifolds.
High Power
Quadrajet
Spread Bore
Spread Bore
GM spread-bore. Small primaries, large secondaries. 1965–90 Chevrolet, Pontiac, Buick, Olds.
GM Spread Bore
2-Barrel
2300 Pattern
2300 Pattern
Smaller 2-barrel bolt pattern. Inline-6, small-displacement V8 and economy engines.
2-Barrel
Rochester 2GC
Small Bore
Small Bore
Small bore 2GC pattern. Direct bolt-on replacement for Rochester 2GC small bore applications.
Rochester 2GC
Rochester 2GC
Large Bore
Large Bore
Large bore 2GC pattern. Direct bolt-on replacement for Rochester 2GC large bore applications.
Rochester 2GC
Carter BBD
Jeep Pattern
Jeep Pattern
Specific to 1971–1986 Jeep CJ with the AMC 258 / 4.2L inline-six.
Jeep Specific
Autolite 1100
Ford Pattern
Ford Pattern
1-barrel round pattern for classic Ford 170/200/250 inline-six engines, 1960s–70s.
Ford Classic
Still not sure?
Bring your intake in to Billy's and we'll measure it free of charge - or call us and describe what you have.
Give us your estimated engine output and we'll narrow down the right system.
Base = throttle body only, you supply fuel system. Master = pump, filters and hose included. Stealth = hidden under a carb-style air cleaner.
Sniper EFI Frequently Asked Questions
What carburettor flange do I have?
The most common flange is the Holley 4150 square bore, found on virtually all Holley, Edelbrock and aftermarket performance intakes. The Quadrajet spread bore is common on 1965-1990 GM muscle cars including Chevrolet, Pontiac, Buick and Oldsmobile. Download the Holley printable flange template to confirm your pattern, or bring your intake into Billy's Speed Shop and we'll measure it free of charge.
What is the difference between a Sniper EFI Base Kit and Master Kit?
A Base Kit includes the Sniper EFI throttle body and sensors only - you supply the fuel pump and plumbing. A Master Kit adds a complete EFI fuel system: inline pump, pre and post filters, 20 feet of 3/8" EFI hose and all fittings. If your vehicle is still running a mechanical carburettor pump, the Master Kit is the better choice and better value.
What fuel pressure does Sniper EFI require?
Sniper EFI requires an EFI-compatible high-pressure pump maintaining 58-60 PSI at all conditions. Standard carburettor mechanical pumps produce only 5-7 PSI and cannot be used. A minimum 255 LPH electric pump is recommended for naturally aspirated builds up to 650hp.
Can I control ignition timing with Sniper EFI?
Yes - optionally. Sniper EFI can control ignition timing when paired with a HyperSpark distributor and ignition box. However timing control is not required to run the system. The Sniper will self-tune fuel delivery using just a tach signal from your existing distributor. Holley recommends getting the engine running on EFI first, then adding timing control as a second step.
Is Holley Sniper EFI available in the UK?
Yes. Billy's Speed Shop is an authorised UK Holley distributor. All Sniper EFI systems listed here are available with UK stock. Prices include VAT and any applicable import duties - no hidden fees at checkout. We also fit and tune EFI systems in-house.
What is Sniper EFI Stealth and how is it different?
The Sniper Stealth range uses a carburettor-style outer housing that conceals the EFI throttle body beneath a traditional air cleaner. From the outside it looks indistinguishable from a Holley carburettor - popular for show cars and resto-mods. All the self-tuning EFI benefits are retained.
Need Help Choosing or Fitting?
Billy's fits and tunes EFI systems in-house. If you're unsure about flange pattern, fuel system spec or ignition compatibility, call us before you order and we'll sort it out.