Why the 5.7, 6.4 and even Hellcat Hemi swaps are the holy grail of Jeep power — and what it actually takes to do one right.
There’s a reason every Wrangler owner eventually searches “Hemi swap JK/JL” — it’s the perfect match.
The Jeep platform was built for low-end torque, crawling, towing and highway cruising… and the factory V6 just doesn’t deliver the power or sound many owners want.
A properly done Hemi swap transforms a Jeep from “capable” to “effortless” — mountains, mud, towing, overtaking, dunes, crawling… it all becomes easy. And unlike LS swaps, the Hemi is a native Jeep/Chrysler engine, meaning cleaner wiring, factory ECU compatibility, and OEM drivability.
This guide explains everything you need to know — from engine choices, required parts, gearing, legality, cost, and how JEEPLAB supplies the hardware you need to build it your way.
✅ Why Swap a Hemi Into a Jeep?
✔ Instant torque — no more “foot flat waiting for RPM”
✔ Sounds like a Jeep should sound
✔ Perfect for bigger tyres + re-geared diffs
✔ Reliable, proven Mopar platform
✔ Works with factory Jeep electronics & systems
✔ Massive towing improvement (especially Gladiator)
✔ Makes 35s or 37s feel like stock tyres again
This is NOT about drag racing — it’s about drivability.
✅ Hemi Engine Options for JK/JL/Gladiator
| Engine | Power / Torque | Best For | Notes |
|---|---|---|---|
| 5.7L Hemi | 260–290kW / 500–540Nm | Best budget swap | Easy, reliable, plenty of torque |
| 6.4L 392 Hemi | 350kW / 640Nm | Maximum NA power | Factory Jeep 392 engine |
| 6.2L Hellcat SC | 520kW+ | Extreme builds only | Overkill, needs axle upgrades |
Everything people now love about the 392 Wrangler?
Jeep guys have been doing that swap for a decade already.
✅ Stock Jeep Engine vs Hemi Swap
| Engine | Power | Torque | Notes |
|---|---|---|---|
| 3.6 Pentastar | 209kW | 347Nm | Works… but struggles with 35s/37s |
| 2.0T | 200kW | 400Nm | Punchy but not exciting |
| 3.0 EcoDiesel | 190kW | 600Nm | Good tow option, expensive |
| 5.7 Hemi | 260–290kW | 500+Nm | Best value swap |
| 6.4 Hemi | 350kW | 640Nm | Factory Jeep V8 spec |
| Hellcat | 500kW+ | 850+Nm | Needs full driveline build |
✅ The Parts You MUST Change in a Hemi Swap
A real Hemi swap is not just engine + mounts.
These systems must be matched:
| System | What Changes |
|---|---|
| Engine Mounts | Hemi-specific brackets & isolators |
| Cooling | Alloy radiator, hoses, overflow, higher flow pump |
| Exhaust | Hemi headers + Jeep-specific down pipes |
| Wiring | ECU integration, harness adapters |
| Fuel System | Regulator & line capacity |
| Power Steering | Hemi pump compatibility |
| Driveshaft Angles | Depending on lift & gearbox |
| Gearing | 4.56 / 4.88 recommended for 35s/37s |
| Air Intake | Hemi-sized MAF & filter route |
A Hemi swap that overheats, surges or stalls is 100% a “wrong parts” issue — not a Hemi issue.
✅ The 8-Speed Auto Advantage (ZF 8HP)
The newer JL & Gladiator 8-speed auto (same family as Trackhawk/ZF8) makes Hemi swaps even better:
✔ Perfect ratios
✔ Better cooling
✔ Stronger than old 5-speed
✔ Crisp downshifts, no hunting
✔ Can handle 6.4 and Hellcat torque
A 5.7 Hemi + 8HP auto feels like a modern factory V8 Jeep — not a retrofitted engine.
✅ Australian Legal & Engineering Notes
Yes — Hemi swaps CAN BE legal in Australia if done properly.
🔹 Must meet ADR emissions for YOUR vehicle year
🔹 Must pass VSB14 guidelines
🔹 Must be engineer certified
🔹 Cats, EVAP, OBD2, and ECU must remain functional
🔹 Hellcat swaps require extra brake & axle requirements
If it passes emissions, brake test & engineering — it’s legal.
✅ Cost Breakdown (Real-World Estimates)
| Swap | DIY Parts Cost | Installed by Workshop |
|---|---|---|
| 5.7 Hemi | $12k–$18k | $25k–$35k |
| 6.4 Hemi | $16k–$24k | $35k–$45k |
| Hellcat 6.2 SC | $30k–$45k | $55k–$80k |
Most swaps are 5.7 or 6.4 — Hellcat builds are rare and expensive because they require:
➜ Stronger axles
➜ Bigger brakes
➜ Upgraded fuel system
➜ Heat management upgrades
✅ JEEPLAB Hemi Swap Parts Supply ✅
We don’t install — we supply the parts that make the swap possible:
🔧 Engine Mount Kits (JK/JL/Gladiator)
🔧 Radiators & High-Flow Cooling Kits
🔧 Hoses, Lines & Fittings
🔧 Exhaust / Header Kits
🔧 Wiring Integration Parts
🔧 Accessory Drive / Bracketry
🔧 Power steering + AC routing solutions
🔧 Used 5.7 & 6.4 engines sourced on request
🔧 Full parts lists for DIY or workshop installs
“No mystery. No hunting US forums. We supply what actually fits.”
✅ FAQ
Do I need to re-gear after a Hemi swap?
Yes. 35s or 37s + Hemi + stock gears = terrible highway RPM.
Can the stock axles handle a Hemi?
5.7 yes. 6.4 yes. Hellcat? No — upgrade first.
Can I keep factory AC, cruise, dash, etc.?
Yes — with the right harness/ECU routing.
Can JEEPLAB recommend installers?
Yes — we can point you toward trusted workshops.
🏁 Trackhawk Comparison
The Trackhawk is the factory Hellcat Jeep — 700hp, 8HP auto, AWD.
The only difference?
Wrangler & Gladiator owners build them… not buy them.
✅ Final Word
A Hemi swap isn’t just about power — it’s about correcting what the Jeep platform was always missing: torque with no effort.
Whether you’re building a touring Gladiator, a 392-style JL, or a JK rock rig:
The right parts = a factory-smooth V8 Jeep that just works.
JEEPLAB supplies the hardware.
You choose the installer.
We ship Australia-wide.
📩 Want a full Hemi swap parts list? Contact JEEPLAB.
