When Chevrolet Performance engineers began development of the LSX454R racing crate engine, building the most powerful engine ever from the company wasn’t on the checklist. They were after durability first and foremost, but the power rating was a happy – and important – consequence.
“We wanted big power, of course, but more than that, we wanted to give racers a reliable, low-maintenance engine that would round after round and race after race throughout the season and require little more than oil changes and the occasional valve-lash check,” says Rocko Parker, lead engineer. “In fact, this engine should go several seasons without the need for any major refreshing. That was more important to us than the final dyno number.”
For the record, this 13.1:1, naturally aspirated and single Dominator-fed big-inch LS engine is officially rated at 770 horsepower at a 7,000 rpm and 612 lb.-ft. of torque at 5,600 rpm. Those figures might be a little conservative. Notably, that’s a 50-horsepower increase over Chevrolet Performance’s own ZZ572/720R drag race crate engine – an old-school big-block that, while it cranks out another 70 lb.-ft. over the LSX454R, comes up short on horsepower even with 26 percent more displacement. That’s huge.
“There’s almost no limit to what you can accomplish with an LS engine,” says Parker. “The LSX DR [drag racing] heads we used on the LSX454R flow incredibly well, but the entire intake side of the engine – the manifold, carb and camshaft – is designed with little restriction to move as much air as possible at high rpm.”
Sturdy bottom end
From the cylinder heads up, the LSX454R is unique, but its foundation is the sturdy bottom end that underpins the street-based LSX454, including an all-forged rotating assembly and the LSX Bowtie cylinder block. The latest version of the block, which includes provisions for six-bolts-per-cylinder head clamping over the production-spec four bolts per cylinder, is stronger than ever and supports even greater capability, should the owner decided to spray the engine. The 13.1:1 compression ratio is too high for supercharging or turbocharging, but that’s a topic for an entirely different story.
“Again, durability was the overriding goal for the engine and the LSX Bowtie block helps give us that,” says Parker. “We could have definitely squeezed a few more horses out of it, but we were concerned about longevity and how many quarter-mile passes it could take. The aim was to make sure it could withstand about two years of quarter-mile racing without the need for major maintenance.”
Engine should run mid-9s
To that end, Parker says his engineers targeted camshaft lift below the 0.750-inch threshold and kept engine speed to 7,100 rpm. When it came to validating the engine’s dependability, the engineers used and electric dynamometer to simulate quarter-mile racing.
It will go the distance, round after round.–Rocko Parker, GM engineer
600 dragstrip simulation runs
“We did that for 600 trips down the simulated drag strip, with only a shut down every 50 events to verify valve lash and the health of the engine,” says Parker. “It was an aggressive validation case the equivalent of about 8.5 hours of non-stop racing, not counting the health checks, but that’s what we wanted in the pursuit of a reliable bracket engine that someone will use in Super Comp, Super Gas and classes like that.”
In the real world, 600 quarter-mile passes is a lot for most racers – something like six rounds every single week for two years. That’s a lot of racing. If the LSX454 proves as strong in the field as it did in the lab, those 770 horses are going to pull many a race car into the winner’s circle.
“We weren’t easy on the engine during development and it never failed,” says Parker. “It was making the same horsepower on the last quarter-mile simulation that it did on the first.”
The LSX454R is assembled at a specialized Chevrolet Performance facility in the Detroit area that blends the best of hand-assembly and production-line techniques. Every component associated with the rotating assembly and the respective holes they fill in the block are mic’d with ultra-precise air gauge tools and their specifications recorded in a master file for each engine. Think of it as high-tech blueprinting.
Computer-controlled and calibrated torque wrenches ensure consistency with every engine, too, but they don’t replace the eyes and experience of specially trained builders who guide each engine from start to finish. There are only four stations involved with each engine’s assembly, with a single builder at each one responsible for specific tasks. In the first station, the rotating assembly and engine block are inspected, measured and prepped for assembly. At the second station, the bottom end of the engine is installed and at the third stage, the heads and other top-end parts are added. The final station is an inspection stop, where each engine subjected to a roster of checks, including leaks, compression and oil pressure.
We asked Chevrolet Performance to let us document the assembly process and they obliged. It was a fascinating look at how a hardcore racing crate engine comes to life, which we are sharing in the accompanying photos.
“If you want to race and not wrench on your racing engine, the LSX454R fits the bill perfectly,” says Parker. “It will go the distance, round after round.”