The best in-tank fuel pumps for LS/LT swaps deliver reliable fuel pressure, high flow, and easy installation. This guide targets buyers doing square-body and GM swap projects who want dependable, drop-in solutions without complex splices. The top picks below cover 340–450 LPH pumps, EFI and TBI approaches, and compatibility with gasoline and E85. Each product section highlights who it’s best for and why, plus a practical limitation to consider. A quick summary table is provided to compare core specs at a glance.
| Product | Best For | Flow (LPH) | Notes |
|---|---|---|---|
| Lanotech 340LPH High-Flow | LS/LT swap in classic Square Body trucks | 340 | Hanger + sending unit included; -6AN fittings |
| EVIL ENERGY 255LPH | EFI systems needing solid mid-range flow | 255 | 43 PSI kit; 15–90 PSI range |
| KEMSO 340LPH | High-horsepower NA/turbo/supercharged builds | 340 | Supports up to 600 BHP; USA support |
| Lanotech 450LPH Hanger Kit | High-performance LS/LT swaps with flex-fuel | 450 | In-tank, E85 compatible; no tank modification |
| TBI to LSx 58PSI Kit | 1982–1995 GM TBI to LSx swaps | 58 trailing | Direct drop-in, complete kit |
Lanotech Fuel Pump for 1973-1991 LS/LT Swap 340LPH High Flow
The Lanotech 340LPH pump is designed for 1973–1991 Square Body trucks with EFI LS/LT swaps. It eliminates in-tank splices and solder joints, reducing a common failure source. Best for buyers seeking a straightforward, drop-in LS swap solution with a dedicated sending unit and AN fittings. Caution: verify compatibility with your exact truck model and wiring harness if using alternate tank components.
EVIL ENERGY EFI 255LPH Electric In-Tank Fuel Pump Kit
EVIL ENERGY offers a 255LPH high-flow option for 12V EFI systems, with a 43 PSI kit that can operate between 15 and 90 PSI. This makes it a solid choice for moderate-performance builds and kits that prioritize a compact, affordable upgrade. Best for enthusiasts who need a reliable 58 PSI-equivalent flow when paired with regulators. Limitation: high-impurity fuel may shorten pump life and performance.
KEMSO 340LPH High Performance Fuel Pump
KEMSO’s 340LPH pump targets higher power builds, supporting up to 600 BHP in NA, turbocharged, or supercharged setups. It comes with USA-based support and is designed for gasoline or E85. Best for hot-rodders and performance enthusiasts who want robust fuel delivery with domestic technical support. Caution: ensure your fuel system components handle ethanol blends and verify regulator compatibility.
Lanotech 450LPH Fuel Pump Hanger & Sending Unit
This kit is built for 1973–1991 Chevy and GMC Square Body trucks and supports LS/LT engine swaps with no fuel-tank modifications. It’s E85 and gasoline compatible and uses a 450LPH pump for high-demand builds. Best for flex-fuel projects and those seeking a high-flow, in-tank solution. Limitation: higher flow may demand compatible regulators and a robust return system.
TBI to LSx Swap Direct Fit Fuel Pump Kit
Designed as a direct drop-in for 1982–1995 GM TBI vehicles, this kit delivers 58PSI and includes pump, filter, strainer, tank seals, and clamps. Best for TBI-to-LS swaps that want a simple, integrated solution without cutting or splicing. Choose this if you need a complete kit that minimizes modification. Limitation: pressurization relies on LS-compatible regulator or rail regulator setup.
Buying Guide
What should I consider when choosing an in-tank fuel pump for an LS swap?
- Flow vs. horsepower: Higher LPh supports more horsepower but may require regulator and wiring upgrades. Match pump flow to your target power and fuel system design.
- Fuel type compatibility: Verify compatibility with gasoline and ethanol blends (E85) if you plan flex-fuel use.
- Swap compatibility: Ensure the pump, hanger, and sending unit fit your truck model and the LS/LT engine family you’re using.
- Installation complexity: Drop-in kits reduce modification risk. Some require tank adapters or additional mounting hardware.
- Electrical load: Check amperage draw and wiring to avoid overheating or fuse issues in your build.
Which features improve reliability in an LS swap?
- Integrated sending units and proper hanger designs reduce splices and failure points.
- Fuel compatibility with ethanol blends extends life in flex-fuel builds.
- Stable pressure delivery with regulators or rail regulators ensures consistent engine performance.
How do you compare 340LPH vs 450LPH pumps?
- 340LPH is typically sufficient for many NA and lightly boosted LS builds; it pairs well with stock or mild regulator setups.
- 450LPH provides higher flow for high-horsepower builds or boosted engines, improving fuel delivery at higher RPMs but may demand stronger fuel-system components.
FAQ
- Do these pumps require professional installation? Most kits are designed for enthusiasts who follow factory diagrams; some tasks may require mechanical wiring and tank work.
- Are these pumps compatible with standard GM towers and hangers? Most are designed as direct-fit or with minimal modification for LS/LT swaps.
- Will a higher flow pump cause regulator issues? Not if the regulator is chosen to match the target pressure and flow.
- Can I mix ethanol with gasoline in these pumps? Yes, most listed pumps are compatible with E85 or ethanol-blended fuels.
- Is an in-tank pump safer than an external pump? In-tank pumps reduce heat exposure and can improve reliability for LS swaps with integrated systems.
- What about spare parts and support? Some brands offer USA-based support and parts, which helps during installation and maintenance.