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Jeep Engine Swaps - GM TBI V8

Lo5 V8 Engine
John White | Writer
Posted October 1, 2008

Is This The Very Best Mill To Swap Into A Jeep?

From 1987 to 1995, GM produced what was coded the "LO5" TBI 350. This engine combo was based on the solid 350ci V8 long-block with a throttle-body fuel-injection (TBI) system mounted directly on top of the intake manifold. This form of "wet intake" injection system didn't produce the higher horsepower figures later obtained with "dry intake" multiport fuel-injection (MPI) systems such as L98 or LT1 F-bodies (Vette and Camaro). However, the torque curve for the TBI engine was a perfect fit for 4x4s. Horsepower and torque values for the LO5 increased slightly over the production term ending in 1995 with 312 lb-ft of torque and a solid horsepower figure of 210. GM used the LO5 in several passenger cars such as the Caprice, but the most popular fit was the 1/2-ton pickup and Suburban line.

The GM Corvette and Camaro LT1 engine provided an excellent torque curve (high and flat). However, the Opti-Spark ignition mounted at the crankshaft height scared off a number of engine swappers. Early salvage-yard costs were high compared to a TBI engine.

After a few years of production, the LO5 started turning up in a variety of transplants from Jeeps to earlier fullsize trucks. For a number of years, the standard "swap" engine for Jeep builders was the TBI 350. The fuel-injection system on the LO5 is based on a dual-injector pod which is programmed to introduce a conical spray of fuel directly into the top of the intake manifold. This most basic EFI design proved to be perhaps the easiest to diagnose and tune of any to date. Quick ignition, smooth-running, and good fuel efficiency made the LO5 a great pick.

In an engine-swap application, the wiring required to support the TBI LO5 proved to be one of the most inexpensive and basic harnesses for the aftermarket to produce, and that still holds true today. Using the engine wiring harness from the donor vehicle wasn't a huge chore. However, the availability, simplicity, and price of a fresh aftermarket TBI harness, such as those available from Howell Engine Developments, remain hard to pass up.

In today's world of complex injection systems, composite intakes, and expensive wiring systems, the LO5 would seem to be the ideal engine for the salvage-yard searcher. Unfortunately, the chances of finding a low-mileage LO5 in decent condition is made worse by the fact that GM hasn't produced one in 13 years.


Scoggin-Dickey Parts Center
Lubbock, TX 79424
Turbo City
Orange, CA
JB Conversions Inc.
Sulphur, LA 70664
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