Back in 2021 Ryan Lavacot of 2CarPros pulled a 260,000-mile 5.3L LS from a 2001 Chevy Silverado and rebuilt it into a powerhouse that puts out 493 horsepower and 412 lbs.-ft. of torque. He documented the entire build from soup to nuts in this 2CarPros YouTube video series.

Want to build a similar LS? Summit Racing made handy 2CarPros 5.3L GM LS Engine Parts Combos to help you do it.

(Image/Ryan Lavacot)

Since then, Ryan has moved into a new shop and found a home for the 5.3L, a 1955 Chevy Bel Air four-door sedan. Being the giver that he is, Ryan decided to show you what it takes to install an LS engine in a classic vehicle with the How to LS Swap video series on the 2CarPros YouTube channel.

“I want to show people what it takes to remove an old engine and swap a new LS into a classic car,” Ryan explained. “While the car I have is a 1955 Chevy, what you’ll learn applies to most any rear wheel drive car or truck from the 1950s through the 1980s or so. There are a lot of steps to this, but by the end of this series you should be able to put an LS into any classic car you will run across.”


The Car

Ryan found this 1955 Chevy Bel Air sedan through a friend of the family. It will make the perfect cruiser. (Image/Ryan Lavacot)

Ryan found the Bel Air through a friend of the family, who bought the car for the 265 cubic inch small block he needed for an early Corvette restoration project. Being a California resident all of its life, the Bel Air was rust-free underneath and showed just a few areas of surface rust up top. The suspension looked recently rebuilt, the interior was reupholstered (albeit in a non-factory fabric), and all of the trim bits were present. You can see how nice and clean this ’55 is in this ‘Finding the Car video—and please forgive Ryan for calling the car a 1956 at the beginning of it. He’s now on the straight and narrow.

There are three segments posted so far that cover engine removal, engine bay prep, and getting the LS and Turbo 350 transmission ready for installation. We’ll cover the remaining segments as soon as they’re posted.


Episode 1: Taking the Engine Out

The 265 small block comes out of the Bel Air’s engine bay, perhaps for the first time since Chevy built the car almost 67 years ago. We say perhaps because the engine ran like a champ and had some updates like a new carburetor, leading Ryan to believe the engine had been rebuilt at some point. (Image/Ryan Lavacot)

The Bel Air’s engine compartment and the 265 small block were very clean, making removal less of a chore. An external transmission cooler in front of the radiator had to be removed. Radiators with built-in transmission coolers are available for this swap. The previous owner installed a one-piece cooling fan shroud for some reason; Ryan had to unbolt the fan and water pump pulley to remove the shroud and the radiator.


Episode 2: Removing the Transmission

The Bel Air was equipped with a cast iron Powerglide two-speed automatic transmission. An adapter plate mates the transmission to the engine and the starter bolts to the plate instead of the block. Chevy switched to an aluminum-case Powerglide and the more familiar block-mount starter in the early 1960s. If you have a 1955-56 Chevy and want to bolt a Turbo 350, 400, 200-4R, or 700R4 transmission to the stock V8, you will need this Danchuk starter adapter plate. (Image/Ryan Lavacot)

In this video, Ryan removes the stock cast iron Powerglide transmission the proper way using a dedicated transmission jack. If you don’t have the luxury of a lift, you can get a floor-style transmission jack that can be used with the vehicle on the ground. You’ll also see Ryan’s method for painting the firewall and inner fenderwells.


Episode 3: Engine and Transmission Prep

Summit Racing LS conversion engine mounts make installing an LS in a classic, small block-powered Chevy like the Bel Air much easier. The mounts have three slots that allow you to adjust the location of the engine in the car: center, 2 inches forward, and 2 inches back from center. Add a set of clamshell-style motor mounts and you’re in business… (Image/Ryan Lavacot)
…unless you have a 1955 Chevy, in which case you’ll need a set of engine stands like these from Classic Performance that Ryan used. They bolt to the car’s frame, but you will need to remove two rivets to use the holes for the mounting bolts. You’ll also need to drill two additional holes in the top of the frame for the other mounting bolts (4 total for each stand). (Image/Summit Racing)

Now we get to the fun stuff. In this video, Ryan gets the LS engine ready to install by bolting a set of Summit Racing™ Adjustable LS Conversion Engine Mounts, Summit Racing™ Polyurethane Motor Mounts, and a PRW Industries flexplate to the block.

Ryan chose a Summit Racing Turbo 350 automatic transmission and 2,800 RPM stall converter to handle the gear-shifting duties. A dished flexplate and a flexplate hub adapter like this Summit Racing adapter are required to mate the LS engine to the Gen I-pattern torque converter. The flexplate has the proper bolt pattern for the converter, and the adapter makes up the .40 inch difference between the shorter LS crank and the Gen 1 small block crank. (Image/Ryan Lavacot)

Ryan chose a Summit Racing™ Turbo 350 Automatic Transmission and Torque Converter for gear shifting duties. He also shows you the Summit Racing™ Flexplate Hub Adapter required to mate the LS engine to the Gen I-pattern torque converter and the proper procedure for seating the converter to the crank hub.


Episode 4: Engine Installation

Ryan Lavacot of 2CarPros pulled a 260,000-mile 5.3L LS from a 2001 Chevy Silverado and rebuilt it into this powerhouse that puts out 493 horsepower and 412 lbs.-ft. of torque. He documented the entire build from soup to nuts in this 2CarPros YouTube video series. (Image/Ryan Lavacot)

Ryan’s initial idea was to install the engine and transmission as a unit. The core support sat too high to make that happen. Rather than remove the core support, he installed engine and transmission separately. Ryan also found that he needed a set of engine stands designed to fit a Gen 1 small block Chevy in a 1955-57 Chevy. He used these Classic Performance engine stands.

A test fit also revealed that the LS engine’s Gen 4 Camaro oil pan hit the car’s steering linkage. Ryan replaced the pan with a Summit Racing™ Pro LS Cast Aluminum Oil Pan that provided the necessary clearance (approximately a half-inch). The existing windage tray needed to be modified for the oil pump pickup type bracket. Ryan shows you how to do this in the video.

Ryan built the 5.3L LS with an oil pan designed for a Gen 4 (1993-2002) Camaro or Firebird. When he dropped the engine in the Bel Air, he found the pan’s sump hit the steering linkage. The solution was to swap that pan with this Summit Racing Pro LS oil pan designed to fit 1955-57 Chevy passenger cars and a host of other vehicles like 1967-87 Camaros, 1964-73 GM A-bodies, and 1967-74 Chevy/GMC C10 pickups. (Image/Summit Racing)

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Author: Alan Rebescher

Editor, author, PR man—Alan Rebescher has done it all in a 25 year career in the high performance industry. He has written and photographed many feature stories and tech articles for Summit Racing and various magazines including Hot Rod, Car Craft, and Popular Hot Rodding, and edited Summit Racing’s Street & Strip magazine in the 1990s. His garage is currently occupied by a 1965 Ford Mustang.