How to Swap an LS Engine Into Your 1967-1972 GM C10 Truck With A Holley Swap Kit

10 min read

How to Swap an LS Engine Into Your 1967-1972 GM C10 Truck With A Holley Swap Kit

10 min read

One of the most popular LS swap recipients today are the light truck lines offered by Chevrolet and GMC. The C/K series of trucks and utility vehicles were introduced in 1960, with a second generation running from 1967-1972 and a long lasting third generation that carried from 1973-1987. Holley and their supporting brands have been studying and building C10s for years and offer a plenty of performance upgrade products, as well as an inclusive list of LS swap components.

LS swaps are nothing new, but there’s a difference between reading about them in forums versus finishing one right the first time. Planning out an LS swap by mapping out the parts you’re going to need to complete the installation will pay dividends once you start turning wrenches. Buying mounts from company A, headers from company B, with a crossmember from company C can add up to an overall fitment issues as the parts weren’t designed to work together as a whole. It’s best to work with parts from one company all the way through.

Not only does Holley continue to roll out helpful new LS swap components, but they work together with a number of their sister companies to develop products that are engineered, tested and built to work together. This means you get parts that fit right and perform to expectation to help you achieve a professional drivetrain swap

We decided to put their list of C10 LS swap parts to the test by swapping a late-model powertrain into a 1971 Chevrolet C10 Suburban. The ‘new’ driveline was liberated from a totaled 2003 Chevrolet Tahoe. We were able to start the 5.3L and even putt the wreck around the yard before deciding it would be right for our ’71. The engine had about 110,000 miles, sounded good and the trans shifted from what little we could tell and had healthy appearing trans fluid. The swap was a go.

For electronic control, the Terminator X Max was our go-to decision since it has trans controls built into the ECU. The system is easy to program with its handheld monitor, plus we’ll have the capability to plug-in our laptop for some advanced trans tuning and other controls. The Holley site made it easy to boil down exactly what part numbers we needed including the ECU, the injector harness, drive-by-wire harness and more.

The site also has pages dedicated to LS swap applications, including our ’71 Suburban, so it was easy to scroll through the site and find engine mount systems, headers and manifolds, cooling system solutions, fuel system solutions and more. Follow along as we detail our C10 LS swap.

LS Suburban engine removal

Out came the ‘updated’ drivetrain of our C10 consisting of a well-worn TBI equipped SBC 350 and 700-R4 transmission. The engine ran okay with a little knock at start up but the 30-year-old EFI was becoming problematic. Good riddance.

LS Suburban tank hanger

With the engine in place, it was time to bring the fuel delivery system up to LS standards. We went with a Holley Sniper Universal Pump Hanger (PN 19-350) so the new 340 LPH pump could be mounted in the tank. The kit features a low-profile cast ‘hat’ with three ¼” NPT outlets (feed, return and vent) and has a unique mounting design so it can easily be clocked for different applications.

LS Suburban fuel pump adjustments

The fuel pump needs to be installed so the sock is just touching or near the bottom of the tank. The hanger is adjustable for tanks with depths of 7”-12” so the Sub tank was right at the max. The pump is wrapped in a foam sleeve then secured with two clamps. Do not forget to plug-in the electrical connector!

LS Suburban Connector Routing

There’s no good way to start other than heaving the harness onto the engine and begin routing the connectors. Holley designed the harness with plenty of length to reach the ECU and all of the sensor locations.

LS Suburban 02 sensor

The 02 sensor was placed in our existing single 3” exhaust just after the Y-pipe. We liked the sound and routing of our Suburban’s exhaust or we would have gone with one of the Hooker Blackheart exhaust systems for C10s.

LS Suburban radiator

A new Frostbite radiator is equipped to accept the LS steam vent hose but we got lucky with our old radiator as the heater outlet was threaded so a couple adapters were added to connect the steam vent.

With the wiring all connected to the ECU it was time to apply power for the first time. Also, a vacuum line was routed to the internal MAP sensor of the Terminator.

Suburban LS finished

You can’t say it looks original under the hood, but an LS sure fits nice in the engine compartment of any year C10. For now, we stuck the long, clumsy air intake assembly on since it fit but we plan to assemble a tight elbow and cleaner assembly soon. The engine swap itself went smoothly resulting in a professional looking installation. The same can be said for the advanced technology of the Terminator X Max and the fitment of their harnesses and connectors.

Products Used In This Project

Hooker BlackHeart Heavy Duty Clamshell Engine Mount KitVK090152
Hooker BlackHeart Engine Swap Brackets, 1967-1972 GM C10 with Narrow Frame RailsBHS511
Holley GM LS Swap Oil Pan, Rear Sump, 6 Quart Capacity, 1955-1987 GM applications 302-2
Holley GM LS Dipstick and Tube Kit302-15
Mr. Gasket Oil Pan Gasket, 1997-2017 GM LS Engines6665G
Hooker BlackHeart Transmission Crossmember, 1963-1972 GM C10 LS/LT Swap, 4L60E, TH350, 6L80 or 700R471222024HKR-2
Frostbite Aluminum Radiator, 1967-1972 Chevy/GMC C/K with GM LS Swap, 3-Row, 17" Tall CoreFB311
Holley Sniper Diecast 340 LPH In-Tank Retrofit Fuel Module with Return19-350
Holley EFI Fuel System Kit - 40' of 3/8-in. Earl's Vapor Guard fuel hose, Fuel Filter, Clamps, and Hose Barbs 526-10
Holley EFI Terminator X Max, GM LS1/LS6, 24x Crank, EV6 Connectors, DBW Throttle Body, Trans Control550-934
Holley EFI CAN Extension Harness, 9-in. (supplied with ECU) 558-428
Holley EFI LS1/6 (24x/1x) Engine Main Harness (supplied with ECU)558-102
Holley EFI Injector Harness, Early Truck558-214
Holley EFI Terminator Air Temp Sensor554-121
Flowtech LS Swap Exhaust Manifolds, Natural Cast Finish, 2.25-in. Outlet11730FLT


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