Benefits of Stroking an Engine: A Guide to Buying Stroker Kits

Any performance engine builder who’s worth his salt will tell you that the surest way to make an engine more powerful is to make it bigger. What qualifies as a more powerful engine is relative though, because there are 2 very different paths available on the route to more power. If you’re looking for the long-legged, top-end speed at the absolute edge of an engine’s power curve, then a big bore, high horsepower engine is what you want. But on the other hand, if you’re looking for the eye-popping torque that’ll pin you to the seat like an angry rugby prop, then a stroked motor is what you’re after.

Stroking a motor increases its displacement by increasing the distance the pistons travel between its top and bottom centre positions: the full length of their stroke. The added volume of combustible mixture that’s drawn into the cylinders during all that travelling isn’t lost as wasted heat and energy, though. It sets off a longer torquier effort, which, when transferred to the drive wheels, comes on with a vengeance when you tap the accelerator. If this is the sensation you’re looking for from a more powerful engine, then let’s talk about what else stroker motor performance has to offer.

The Advantages of Stroking an Engine

Close-up of attaching crankshaft in the engine

Let’s be honest: there’s an air of mystery about stroking. And that’s because, in all fairness, there’s a staggering number of zero-tolerance calculations to be made if you’re scrounging for one-off stroker components to machine on your own. However, by starting with a high-performance stroker engine kit, you can eliminate all the risky guesswork and get straight to the assembly. In fact, because engine stroking is mainly an exercise in parts-swapping, stroker kit components are designed to be direct bolt-in replacements for OE equipment that can be installed during any solid rebuild.

Assuming you would ordinarily make tunnel boring and torque plating a part of your basic block preparation, fresh main bearings, seals, and a thorough clearance check of the complete rotating assembly are all that’s needed to get a stroked motor turning. There’s no worrying about regrinding an OE cast crank, no searching through parts bins and catalogues for rods to custom machine, and no concerns for piston compression heights or clearances. A stroker kit is going to contain everything needed to build a proper stroker engine, including:

  • A full billet 4340, nitrided and counterweighted stroker crank;
  • H-beam forged connecting rods with ARP bolts; and,
  • Custom billet 2618 pistons, including rings, pins, and locks with your desired compression ratio.

Stroking an engine is the most advantageous way to increase engine displacement and output, without relying on creative parts combinations of parts and machine work. All the turnkey, bottom-end power you could possibly want is available in a single package.

A Stroker Kit Up Close

When you examine them up close, the components used in the best stroker kits effectively solve all of the problems that stroker motor builders have traditionally had to overcome.

  • The increased throws on a stroker crank allow the rods to travel further on each stroke.
  • The longer stroked rods provide the ideal leverage and dwell time for a piston to travel the longer distance.
  • Shorter sleeved, stroker pistons don’t interfere with rod travel over the longer distance.

Component stresses from longer travel distances and the severity of rod angles, along with the need to reduce piston compression heights, are all accounted for by the high-performance materials and precision engineering that goes into these kits. Now, stroker builders rarely need to be concerned with more than ensuring the motor has sufficient oil pickup, and that there aren’t any throw, rod or pan rail clearance problems at the bottom of the block.

Although they’re meant for high-performance applications, stroker engine kits represent the most fundamental reality of engine building: the importance of all the components working together to create the most power. 

Stroker vs Bigger Bore

Close-up of stroker kit

Now, if you’re still up in the air about the practical benefits of stroking an engine, then maybe you should consider how frequently manufacturers themselves turn to longer engine strokes and piston offsets – not necessarily bigger bores – to create more power. Why? Because it’s cost-effective and it works, and you only have to look at a handful of well-known examples to see how committed OEMs are to stroking. 

  • The ubiquitous Holden / GM LS small-block V-8, which is the de facto standard for factory stroking everywhere;
  • Nissan’s long line of infamous RB engines, which are the exclusive products of factory engine stroking; and,
  • Toyota’s indestructible M-series engines, which are all proud beneficiaries of stroker engineering.

The fact that there are aftermarket stroker kits for sale to not only make these engines but other manufacturers’ engines even bigger as well, demonstrates the rationale behind electing to stroke a motor ahead of boring it.

A Stroker Kit Includes Everything  

When you bore an engine, you’ve got much more to do than just boring the block and slapping in a new set of pistons. You’ve got an entire shopping list of the costly cylinder head and valve train parts and work that’s going to need to be done as well. With stroker motor kits, everything you need is in the box; and if you want to move on to upgrading valves and camshafts, you can do it at your own convenience.       

Any Engine can be Stroked, Not Every Engine can be Bored

That’s right. While most engine blocks either lack the cylinder wall depth for boring, or have already been overbored beyond the point of reliability, stroking doesn’t require performing any machine work that would weaken it, or subject it to persistently high RPMs after it’s assembled that would stress it. 

Big Torque Rules 

Bigger bores are great for top-end speed, but just how often do you actually get to drive that fast? Regardless of whether you’re going off-roading, drifting, or just towing a trailer, the bottom-end torque and instant power that strokers produce can’t be beaten.

The Final Word

Close-up of pistons

The consensus among engine builders is clear: the best way to generate big, reliable power, is by building big, reliable engines. There’s nothing exotic about it, but choosing the most beneficial path at the beginning is going to make the outcome that much more enjoyable. A high-performance stroker engine kit is going to give you everything you need to reliably put more stump-pulling grunt to the drive wheels than you can get otherwise. And, you’re going to be amazed at how consistently and predictably your engine’s going to do it. If you’re currently in the market for a way to get substantially more power out of your engine, and you don’t want to do it the most straightforward way possible, then now’s the time to consider what stroking has to offer.