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Swapping A GM 4.8L V8 Into A 1987 Jeep Wrangler

A YJ gets a GM 4.8L V-8 injection

Jay KopycinskiPhotographer, Writer

You’re looking for more power out of your Jeep and your buddy suggests the tried- and-true engine swap to transplant V-8 power. He goads you on, telling you how it’s an easy weekend swap and maybe $1,000 in parts and cold beverages. So, you pull your trusty, but tired, inline-six engine out and bolt that V-8 in over a weekend. But six weeks later, you’re still riding the bus and bumming rides from friends as your Jeep sits idle under your carport.

Truth be told, proper engine swaps require good planning, plus more time and money than almost everyone expects. However, dropping in modern fuel-injected V-8 power in your Jeep, when done well, can inspire a huge grin in the end. We recently had the chance to follow along as Lamb Fab, a custom shop in Gilbert, Arizona, swapped a 4.8L GM V-8 into an ’87 Jeep Wrangler.

The shop started with a very low mileage 4.8L salvaged from a ’01 Silverado pickup. The Vortec LR4 engine is a small-block engine used from ’99 to ’06. It’s the smallest Generation III truck engine and runs a slightly shorter stroke than the very common 5.3L engine. The smaller brother has the same cross-bolted mains and high-flow aluminum heads. The 5.3L version offers some horsepower advantage, while the 4.8L offers a small edge in fuel economy.

For this swap, only the complete engine was purchased because the Jeep already had an AX15 manual transmission that was going to be retained. Advance Adapters offers a fairly comprehensive set of swap parts to do this conversion, and many of those parts were used for this swap.

After it was complete, the Wrangler ran great and has proven to be very reliable and a blast to drive. There’s a good bet that after pulling the stock inline-six and replacing it with the aluminum head, cast-iron block V-8, the final weight of the Wrangler was a few pounds lighter. The fit under the hood is a comfortable one and the owner was quite impressed with the newfound power and the torque of the bigger engine. Follow along and we’ll show you many of the details that went into completing the project.