Boss Hog Drivetrain Tools
Find the Right Stall Range for Your Build
The right stall speed isn’t just an RPM number. It’s about matching the torque converter to your entire vehicle.
Engine torque, camshaft, vehicle weight, rear gearing, tire size, transmission, power adders and intended use can all influence how a torque converter behaves.
Enter the details of your combination below to get a recommended starting stall-speed range for your build.
Tell Us About Your Combination
For the best estimate, provide as much information as you can. Don’t know every specification? That’s okay. The calculator can give you a starting point, and the Boss Hog team can help you fine-tune the recommendation.
There’s no exact formula for stall speed. It depends on your whole combination. This tool gives a starting-point range based on typical setups. Use it as a guide, then let our team dial in the exact converter for your build.
Your Estimated Stall Range
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Based on the information you provided, this is a good starting range for your vehicle combination.
But don’t buy on the number alone.
Actual converter stall can vary depending on engine torque, vehicle weight, gearing, tire diameter and other characteristics of your combination.
Enter your details above for a starting-point estimate.
Calculator Says One Thing. Not Sure It’s Right?
Ask the people who build the converters.
Send us your vehicle, engine, transmission, gearing and intended use. A Boss Hog converter specialist can review your combination and help you determine the right direction.
Have Boss Hog Check My Results →
Or call (888) 267-7464
Why Stall Speed Matters
Your torque converter helps determine how effectively your engine’s power gets to the drivetrain when accelerating from a stop.
A performance converter allows the engine to reach a more favorable portion of its powerband before the drivetrain is fully loaded.
Too Little Stall
Can make a modified engine feel lazy, pull the engine below its useful power range, or work poorly with a larger camshaft.
Too Much Stall
Can create unnecessary heat, excessive slip, poor street manners, or simply be wrong for how the vehicle is used.
The goal isn’t to choose the highest stall speed. The goal is to choose the right stall speed.
What Determines the Right Stall Speed?
Engine & Torque
Two engines making the same peak horsepower can behave very differently. Where and how the engine produces torque affects converter behavior.
Camshaft
Camshaft selection can significantly change an engine’s useful operating range. A larger cam may require additional stall to allow the engine to operate where it makes useful power.
Vehicle Weight
A heavy truck and a lightweight street/strip car can behave very differently with the same converter.
Rear Gear Ratio
Rear gearing works together with your transmission, tire diameter and converter. Gearing needs to match the vehicle setup, particularly with taller tires.
Tire Diameter
Changing tire height effectively changes the final drive ratio. That’s why tire diameter belongs in the calculation—not just transmission and rear gear.
Power Adders
Turbochargers, superchargers and nitrous can dramatically change the torque characteristics and requirements of the combination.
How You Use the Vehicle
A daily-driven street car, tow vehicle, weekend street/strip car and dedicated race car don’t necessarily need the same converter—even with similar engines.
Advertised Stall vs. Actual Stall
Here’s Where People Get Confused.
A converter advertised as “2,800–3,200 RPM” isn’t guaranteed to stall at exactly the same RPM behind every engine and in every vehicle.
Advertised stall ranges are based on a particular vehicle setup, and actual stall can vary depending on the vehicle combination.
Vehicle A
- Naturally aspirated small-block
- Mild cam
- 3.42 gear
- Heavy street car
Vehicle B
- High-torque stroker
- Larger cam
- 4.10 gear
- Lightweight street/strip car
That’s why our calculator should be the beginning of the selection process—not the end.
Modified Your Vehicle? Tell Us.
If you’ve added any of the following, don’t automatically replace your stock converter with a generic “high-stall” unit:
Camshaft • Cylinder Heads • Intake • Headers • Gearing • Larger Tires • Turbo • Supercharger • Nitrous • Trans Brake
Let the Combination Choose the Converter.
Tell us what you’re building and what you want the vehicle to do.
Request a Boss Hog RecommendationTurn the Calculator Into the Next Step
The calculator should help move a shopper toward the right Boss Hog product—not simply give them a number and leave them there.
Calculator → Recommendation → Product
Have Boss Hog Review My CombinationShop Torque ConvertersOr call (888) 267-7464