About this guide
A TJ engine upgrade is a systems project. These conversion components are for 1997–2006 TJ/LJ builds and should be selected around the exact engine, transmission and transfer case.
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The picks, in detail
Novak MMTJ-G3 GM Gen III Engine Mount Kit
Pre-positioned weld-in mounts for fitting GM Gen III engines into a TJ or LJ.
- GM Gen III
- TJ/LJ fitment
- purpose-built mounts
- welding required
Novak CCLS1C GM Gen III Short Headers
Short block-hugging headers for a GM Gen III V8 Jeep conversion.
- short headers
- GM Gen III
- swap-specific routing
- engine-specific
Advance Adapters TJ V8 with AX15 LS Gen III/IV Package
Advance Adapters lists this TJ LS Gen III/IV conversion package for retaining an AX15 transmission in a planned Wrangler TJ swap.
- LS Gen III/IV
- TJ with AX15
- drivetrain-specific package
- AX15-specific planning
Howell LS Swap Wiring Harness
Howell LS wiring harnesses are an established engine-management route for a GM LS-powered TJ conversion when ordered for the exact engine and transmission.
- GM LS engine
- engine-management harness
- purpose-built LS wiring
- engine and transmission must match
Novak E-TX41 Crank Position Emulator
Tachometer-interface module used with CAN-bus Jeep gauges in GM engine conversions.
- tach interface
- GM conversion
- gauge integration
- application-specific
Advance Adapters 713090 TJ Engine Mounts
Advance Adapters conversion mounts listed for 1997–2006 Jeep TJ Wrangler applications.
- TJ conversion
- engine mounts
- established conversion brand
- confirm engine family
Novak LM7 4L60E TJ/LJ Turnkey Powertrain
Novak lists an install-ready LM7 V8 and 4L60E automatic powertrain package for TJ/LJ conversions.
- LM7 V8
- 4L60E automatic
- integrated package
- major project cost
Novak FX3300-T Electric Fan and Shroud
Novak FX3300-T is an electric fan and shroud assembly for TJ/YJ GM conversion cooling.
- fan and shroud
- TJ cooling
- swap-specific cooling
- conversion-only part
Novak SGI-5E Speedometer Interface
Novak SGI-5E signal interface helps integrate speedometer signals in a Jeep engine and drivetrain conversion.
- signal interface
- gauge integration
- solves a conversion detail
- wiring required
What each one costs
Typical price, cheapest first. Tap a name to jump to that pick and its buy link.
Compare any three
| Novak MMTJ-G3 GM Gen III Engine Mount Kit | Novak CCLS1C GM Gen III Short Headers | Advance Adapters TJ V8 with AX15 LS Gen III/IV Package | |
|---|---|---|---|
| Price | $200–$300 | $500–$650 | $1,000–$2,000 |
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Buying tips
- Plan cooling, fuel, wiring, exhaust and drivetrain together.
- Use a conversion supplier’s fitment builder before purchasing parts.
As an Amazon Associate and eBay Partner, toptenpick.com earns from qualifying purchases. Prices and availability are subject to change.