Take a look at this awesome moment of Proline Racing’s First Dyno Session with the 4.9 Hemi (MH8)-Randy Weatherford Breaks New Ground!
When Proline Racing rolls a brand-new platform onto the dyno, the entire drag racing world pays attention. Their first dyno session with the 4.9 Hemi (MH8) wasn’t about chasing a headline number—it was about validating a concept. With Randy Weatherford leading the effort, this session marked the beginning of what could become a game-changing Hemi program for Pro Mod, no-prep, and outlaw racing.
This was controlled development at its finest.
Why the 4.9 Hemi (MH8) Matters
The MH8 4.9 Hemi sits at the crossroads of modern rules and modern engineering. With many classes tightening displacement and power-adder regulations, efficiency is everything. The 4.9 platform is designed to deliver maximum cylinder fill, stable valvetrain control, and repeatable power—not just peak dyno spikes.
In short, it’s built to win rounds, not internet arguments.
The Goal of the First Dyno Session
This initial dyno wasn’t about “turning it up.” Proline’s focus was methodical:
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Verify oiling stability under load
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Establish baseline combustion efficiency
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Confirm valvetrain behavior at RPM
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Validate airflow and sealing integrity
Early dyno sessions are where engines earn trust. This one did exactly that.
Randy Weatherford’s Development Philosophy
Randy Weatherford is known for restraint where others chase spectacle. On a fresh platform like the MH8, that discipline matters.
Key priorities in this session:
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Smooth power curves over abrupt ramps
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Conservative timing to read plugs and data
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Incremental changes instead of big swings
The takeaway: the engine behaved exactly as designed—a critical milestone for any new architecture.
What the Data Revealed (Without the Hype)
While exact numbers weren’t the headline, the data told a clear story:
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Clean, linear power delivery
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Stable oil pressure and temps
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No valvetrain instability at target RPM
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Consistent cylinder behavior across pulls
That kind of consistency is what allows a program to scale safely in later sessions.
Why This Hemi Is Different
Unlike legacy Hemi combinations adapted over time, the MH8 4.9 was designed with today’s racing reality in mind:
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Efficient head geometry for modern fuels
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Robust bottom end for sustained abuse
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Packaging that works with current chassis and turbo systems
It’s a platform built for repeatability under pressure—exactly what Pro Line Racing values.
Implications for Pro Mod and No-Prep Racing
As the MH8 program matures, expect it to slot naturally into:
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Pro Mod combinations needing efficiency over brute force
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No-prep cars requiring controllable torque
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High-stakes outlaw builds where durability decides outcomes
The first dyno session suggests a wide tuning window—gold in classes where conditions change constantly.
Why First Dyno Sessions Set the Tone
Engines that struggle early often stay problematic. Engines that behave early become champions with time. This MH8 session set a strong tone:
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Predictable responses to changes
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No red flags under load
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Data that matched design intent
That’s how winning programs begin.
What Comes Next
With the baseline established, future sessions will likely explore:
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Expanded RPM ranges
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Aggressive timing and boost maps
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Fuel strategy optimization
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Endurance testing for multi-round events
But those steps only happen when the foundation is solid—and this one appears to be.
Final Thoughts: A Quiet but Important Milestone
Proline Racing’s first dyno session with the 4.9 Hemi (MH8) didn’t scream—it confirmed. Under Randy Weatherford’s guidance, the engine showed the kind of behavior that wins races long after the dyno lights turn off.
This wasn’t about hype.
It was about proof.
And for those paying attention, it signals the start of something very serious.
