Unleashing Power: Building a 500HP GM Stroker Engine – Exploring the Battle Between Old School Chevy Small-Block and Modern LS Series
MARCEL VENABLE May 24, 2023 Chevrolet
What It Takes to Build a 500HP GM Stroker Engine
The debate rages between champions of the old school Chevy small-block and fans of the new-school LS series. Which camp do you fall into? When you really take a look at both power plants they’re not that different in the component category. As a matter of fact, many of the rotating internals share the same dimensions if you decide to hop up one of them.
Obviously GM improved some key features when it introduced the LS series engine in late 1997. The redesigned main caps and side-loading bosses improved the block’s strength; and the noticeable lack of distributor, traded for the individual coil packs devoted to each cylinder, made the LS look completely different, and it took a few years for hot rodders to learn how to build power with it. However, hands down, the one major improvement that the LS series has over the small-block Chevy is improved cylinder head design.
So the debate continues: Is the LS series better thanks to more modern technology and engineering? Well, I wouldn’t count out the ol’ small-block Chevy just yet. There’s no question that this engine design has received more research than a NASA rocket ever did. The small-block Chevy is a freak of nature, and it’s surpassed its original design limitations 10 times over. From the days of 265 ci, to today’s 500-ci monster motors, the small-block Chevy is a tough competitor to beat.
OK, I know what you’re really thinking, which one is better, or which one can I make more power with? Well, the answer really is both, because each design is capable of making more power than anyone could ever use, or should have on the street, and because of their production numbers and the availability of aftermarket speed parts, building a performance GM-based engine is the easiest and most affordable option today.
Now let’s focus on how to get the most out of a GM engine whether it’s based on a small-block Chevy or an LS. I’m sure that all of us motorheads know that increasing the displacement in any engine will benefit the horsepower output. There are many ways to increase engine displacement, but the least invasive method is to change the crankshaft’s stroke length. Referred to as “stroking the crank” or “building a stroker,” it’s by far the simplest way to increase the displacement of a performance engine and yield the biggest gains.
If you haven’t heard the term “stroker engine” before, then let me welcome you to world of the 21st century performance vehicle. But, I’ll bet that you have heard the term, so instead, here’s a little background information on one of the most popular engine modifications known to gearhead kind. Let’s start from the beginning: What is a stroker engine really, and why has it been so popular for most of the last 40 years.
Back in the day, drag racers and dirt track racers were in need of a low-buck way to increase horsepower. Racing is an expensive sport, and most spend a fortune on parts to make their vehicle faster. In the late-’60s and early-’70s, the Chevy small-block engine, or the SBC, was the reigning king of power plants in just about everything on four wheels. The SBC was offered in many different cubic inch sizes, including the ever-popular 350-cid passenger car model, as well as the 400-cid model found in some station wagon and truck models. The racer of this time had to be savvy and unafraid of experimentation to gain maximum horsepower from these engines.
It didn’t take long to figure out how to merge the two engines together. The 400 crankshaft had a stroke length over the 350’s crank, when it was installed into the 350 block, it increased the overall displacement size from 350 to 382.7 ci, which when rounded up turned into what we know as the 383 stroker. The result was an increase in the distance that a piston has to travel up and down in the cylinder bore, which literally increases engine displacement or engine size, creating extra power. This changed everything. As the saying goes, there is no replacement for displacement. From that point on hundreds of thousands have been built. It wasn’t long after that other engines were stroked, like Fords, Mopars, imports and even diesel engines. The mod became the poor man’s race engine and started the street performance revolution.
Throughout the years, many paid for the abuse they were inflicting onto their factory parts. Stock cast components were no match for the high rpm requirements. Parts began to fail, which opened the door for aftermarket companies to improve parts and increase the numbers of this sought-after combination. Stronger forged parts made their way into machine shops, as well as new piston and cylinder head designs, which increased numbers and soon surpassed the old square engine benchmark of 383 hp. In fact it’s not unheard of for engine numbers to surpass 500 hp, street driven on pump gas. The best part of this whole grand experiment is the fact that engine builders didn’t quit at 382.7 ci. It’s now pretty common to change bore size to a larger diameter or even increase the stroke to gain more cubic inches. Many aftermarket parts manufacturers now offer a variety of different sizes of crankshafts and connecting rod lengths that will change overall displacement size. One of the most popular engines to stroke today is the LS series engine which shares some of the same principles of the earlier SBC design.
We wanted to get a better idea of what makes a good stroker combination, as well as what it takes to build one. What we discovered is that there is a ton of information out there to digest and a few different options depending on what your truck already has. To give our readers a better idea of the options that are available, we decided to look into building a pair of the most commonly stroked engines. One is the conventional SBC with 383 cubic inches, and the other is the latest popular stroker combination, a 6.0L LS truck engine stroked out to 408 ci.
LS ENGINE: 2002 6L IRON TRUCK BLOCK STROKED FROM 364 CID TO 408 CID
Small-block Chevrolet engine: blueprint iron block stroked to 383 cid