Blog

Discover the best EFI kit options for 350 engines, focusing on reliability, compatibility, and ease of installation. This guide highlights five kits that suit different goals—from full EFI upgrades to robust rebuild components for a classic 350 build. Whether you’re restoring a vintage street cruiser or building a high-performance daily driver, these picks help you choose the right kit for your needs.

Note: The products listed are suitable for various 350 engine builds, from full EFI conversions to supporting components. The table above compares who each product is best for and why it was selected, helping you decide quickly which kit fits your project.

MSD Atomic EFI Master Kit With Fuel System

Check Price on Amazon

This kit provides a complete EFI solution for 350 engines, integrating an EFI control system with an included fuel pump. Best for buyers seeking an all-in-one conversion that reduces additional component sourcing. It supports 8 connections and CARB compliance, aiding installation in street-driven builds.

Best for: Enthusiasts wanting a turnkey EFI setup for a clean conversion. Not ideal for those seeking only mechanical fuel delivery components without an EFI harness.

Caution: Data notes CARB approval; verify local emissions requirements before installation.

TH350 Turbo 350 Transmission Raybestos Stage 1 Master Rebuild Kit

Check Price on Amazon

This master rebuild kit from Raybestos includes high-quality clutches, premium gasket kit, and complete components to refresh a TH350 transmission. Best for buyers restoring a classic TH350 with a focus on durability and reliability. The kit emphasizes American-made friction plates and comprehensive seals.

Best for: Builders seeking a high-quality, all-in-one rebuild for Stage 1 performance. Choose this if you want robust parts from a trusted supplier and a straightforward rebuild path.

Caution: This kit is focused on Stage 1 refresh; advanced performance mods may require additional components or adaptations.

COMP Cams K07-467-8 XFI Hydraulic Roller Kit

Check Price on Amazon

Designed for GM LT1/LT4 platforms, this hydraulic roller kit offers strong mid-range and top-end performance. Best for buyers aiming to optimize EFI-assisted power with a cam profile designed for 2,000–6,000 RPM operation. Requires compatible headers, gears, and a modified computer for optimal results.

Best for: Performance-oriented builds that prioritize higher RPM power and a modern cam profile. Avoid if you need a simple stock-like torque curve or if system compatibility is uncertain.

Caution: Requires additional engine modifications such as headers and tuning to maximize benefits.

TH350 Turbo 350 Transmission Raybestos Stage 1 Red Less Steel Rebuild Kit

Check Price on Amazon

This Stage 1 rebuild kit from Raybestos focuses on red friction plates and essential components like seals, gaskets, and O-rings, excluding steel clutches. Best for buyers who want a reliable rebuild with a leaner parts set while still delivering dependable engagement and durability.

Best for: Budget-conscious rebuilds that still require top-tier components. Choose this if you already have some parts and want to complement with essential stages without added steel plates.

Caution: The absence of steel plates may affect heavy-duty applications; verify your torque and driving needs before selecting this kit.

Holley Sniper EFI Electric Fuel Pump Kit

Check Price on Amazon

This Holley Sniper EFI kit includes a 350 lph electric fuel pump and installation components designed to support EFI or carbureted systems. Best for buyers needing a versatile pump that can serve EFI upgrades or retrofit projects. It also features a factory-style rollover vent valve and a pre-calibrated sending unit aligned with standard gauges.

Best for: Buyers seeking a flexible fueling option that can support multiple EFI configurations. Choose this if you want proven Holley reliability and a kit that reduces setup complexity.

Caution: Ensure compatibility with your fuel system layout and wiring harness; some setups may require additional fittings or adapters.

Buying Guide

• EFI scope: Decide between a full EFI conversion kit (like the MSD Atomic) or components that complement an existing system (fuel pump, cam kit, or gaskets).
• Vehicle purpose: Street cruising vs. performance off-tune applications influence cam selection, fuel delivery, and rebuild parts.
• Compatibility: Confirm engine family (GM 350, LT1/LT4, etc.), transmission compatibility, and emissions requirements for your locale.
• Installation effort: All-in-one kits simplify wiring and plumbing; separate components may require more troubleshooting but offer customization.
• Reliability and support: Opt for parts from brands with established service networks and documentation to aid installation.
• Budget planning: Balance the cost of a complete EFI conversion against staged upgrades and rebuild items based on project goals.

FAQ

• What is the primary benefit of an EFI kit for a 350 engine? It provides precise fuel delivery, easier cold starts, and improved tunability for performance and emissions.
• Do I need a new transmission with an EFI upgrade? Not necessarily, but a matching upgrade can improve reliability if the drivetrain has high-mileage or stressing loads.
• Can a standalone fuel pump be used with an EFI system? Yes, but ensure the pump flow rate matches the EFI kit’s requirements and the system’s pressure range.
• Is CARB approval important for street cars? CARB approval matters in states with strict emissions rules; verify local compliance before install.
• What should I consider when choosing a cam kit for EFI? Consider RPM range, valve lift,Duration at .050″, and compatibility with your EFI controller and headers.
• Are rebuild kits suitable for daily drivers? Yes, quality rebuild kits from Raybestos provide reliability for daily driving when matched to use-case and torque needs.