See How a Motorcycle Guy Builds a 500 Horsepower LS Turbo Engine

Matthew Bochnak runs the How To Motorcycle Repair website and MatthewMCRepair channel on YouTube. If something is ailing your street or motocross bike, chances are Matt has a post or video that will help you diagnose and fix the problem.

But Matt has a little secret: he likes horsepower, and lots of it. His power platform of choice is a 1970 Chevy Chevelle he’s owned for 15 years.

During that time, he replaced the four-wheel manual drums with C5 Corvette disc brakes, rebuilt the front suspension and added tubular upper control arms, and converted to a quick-ratio power steering box. Under the hood was a small block 350 with a Holley four-barrel carburetor, headers, and other minor upgrades.

That engine simply would not do, so Matt decided to build a turbocharged LS engine for the Chevelle. Being a mechanical engineer by trade, he did a lot of research and came to the conclusion that a 5.3L iron block LS with a stock bottom end and stock cylinder heads would be able to handle around 500 horsepower at 14 PSI of boost running either gasoline or E85.

Figuring everyone loves horsepower whether it’s on two wheels or four, Matt has documented the build from teardown to turbo plumbing—39 episodes and counting as we write this. He’s nothing if not thorough.

The Build
The 5.3L came out of a 2005 GM truck with about 140,000 miles on the clock. Matt tore it down to the bare block and evaluated the condition of the parts. The block was in great shape; the cylinders still had the factory crosshatch and just needed a ball hone to clean them up.

Matt sent the crankshaft out to have the journals polished, and he cleaned the rods and pistons using a home-built vapor blast cabinet. Also known as wet blasting, vapor blasting mixes water and abrasive media (usually fine glass bead or soda) under pressure to remove grease, rust, factory coatings, and other contaminants from parts. The process is quicker than traditional dry blasting and much gentler on metal, leaving a very smooth finish.

Before disassembling the engine, Matt did a leakdown test. He found 20% to 75% leakage in all cylinders thanks to badly pitted exhaust valves and seats. He vapor-blasted and lapped the valves, then sent the heads to the machine shop to be decked and get a three-angle valve job. The shop assembled the heads with new PAC Racing valve springs, retainers, and seals.

With the parts cleaned, machined, and rebuilt, Matt put the long block together. He installed new cam bearings and replaced the factory camshaft with a hydraulic roller cam rated at 223°/230° duration @ .050 and .585 inches of lift. Summit Racing carries a Trick Flow Track Max® cam that is comparable at 228°/230° duration @.050 and the same .585 inches of lift.

Matt then installed new main and rod bearings and assembled the bottom end. He used a set of Summit Racing piston rings gapped to .027 inch as recommended for forced induction applications. He also installed a new Cloyes timing set and a Melling oil pump.

The rebuilt cylinder heads were bolted to the block using new bolts and Chevrolet Performance MLS head gaskets. Matt reused the factory rocker arms and dropped in new LS7-style lifters. Even though the heads were decked, he lucked out and was able to use stock-length pushrods.

Fast-forward a bit and the 5.3L is now in the Chevelle sporting the factory truck intake manifold, 80 lb. fuel injectors, a Holley LS swap oil pan, and a sweet VS Racing turbo hanging off the front passenger side. Matt even built his own crossover and down pipes. There is still a lot to be done, but we’ll be bringing you updates on this project as Matt works toward his goal of 500 horsepower. In the meantime, visit the MC Motorcycle Repair YouTube channel and watch all of the current build episodes. Grab some drinks and snacks—you’ll be watching awhile.

Parts List
Below is a list of parts or equivalent parts Matt used to build the 5.3L, all available at Summit Racing:
• Clevite Cam Bearings
• Sealed Power Main Bearings
• Clevite Rod Bearings
• Summit Racing Piston Rings
• Mahle Cam Seal
• Cloyes Heavy-Duty Timing Set
• Melling Standard Volume Oil Pump
• PAC Racing Valve Springs
• Summit Racing LS7 Hydraulic Roller Lifters
• Chevrolet Performance Head Gaskets
• Chevrolet Performance Head Bolt Kit (2 required)
• Holley Retrofit Oil Pan Kit
• Hooker Blackheart Engine Swap Motor Mounts
• Anchor Industries Motor Mounts for 1998-2002 Camaro
• Restoparts AC Delete Panel
• VS Racing 44mm Wastegate
• Holley Terminator X Engine Management System

Tools
• ARP Thread Chaser
• Summit Racing Cam Bearing Tool
• Total Seal Piston Ring Filer
• Summit Racing Ring Compressor