There’s no replacement for displacement. It’s an adage as old as hot-rodding and one of the set-in-stone truisms. It’s also the thought process behind the ever-increasing popularity of stroker engines. Back in the day, the most popular combo was turning a common 350 small-block into a 383. But today just about any mill can get the stroker treatment. The real gain of any increase in displacement is torque. It’s why a big-block almost always beats a small-block in this department.
If you’re building an engine, and you need to buy a rotating assembly, then going with a stroker makes even more sense because the cost of a stroker crank and rods is only a little more than the stock-sized stuff. For example, Lunati sells their 355ci Sledgehammer rotating assembly for $2,362. But their 383 kit is only $2,404. That’s 28 additional power-producing cubes for a paltry 42 bucks. No other speed part gives you such a return on your performance dollar than a stroker. Well, maybe nitrous, but that’s another story for another time.
Like all good things, you can take the theory too far. Go too big on the bore and you can weaken the cylinder walls to the point of failure. You can also run in to overheating problems. Push the length of the stroke to the ragged edge and you could experience another set of failures: the biggest problem can occur when the piston reaches the bottom of its stroke; this is known as bottom-dead-center (BDC). If too much of the piston extends out of the bottom of the cylinder bore, and the piston isn’t designed for this, the piston can rock, scoring the cylinder walls thus eventually junking up the engine. That’s why it’s always good to check with the manufacturer on what they recommend. We also think a good way to go is with a stroker kit. In a kit the parts are designed to work together in a particular application rather than hobbled together in the hopes they are mechanically compatible.
Lunati and Wiseco have been working together to make sure the stroker kits they offer work. And more importantly, are reliable. The pistons in their LS stroker kits are specifically designed for LS applications. This is critical since every detail matters when you’re pushing the stroke to the ragged edge of what’s possible with a stock-sleeved cylinder.
We’ve been itching to put a bit more power under the hood of our ’68 Camaro, Bad Penny. The LS2 currently in it is running the stock GM short block with a medium-sized COMP cam, FAST 90mm intake, and some sweet AFR 205 heads. It made good power, but for how we use the car, more low and midrange torque would make it quicker—hence more fun.