Best Choice Jeep Motor Upgrade

Illustration for choice jeep motor upgrade
Illustration

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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.

# Product Price Where to buy
1 Novak MMTJ-G3 GM Gen III Engine Mount Kit $200–$300 Amazon
2 Novak CCLS1C GM Gen III Short Headers $500–$650 Amazon
3 Advance Adapters TJ V8 with AX15 LS Gen III/IV Package $1,000–$2,000 Amazon
4 Howell LS Swap Wiring Harness $600–$1,000 Amazon · eBay
5 Novak E-TX41 Crank Position Emulator $175–$250 Amazon
6 Advance Adapters 713090 TJ Engine Mounts $200–$400 Amazon
7 Novak LM7 4L60E TJ/LJ Turnkey Powertrain $17,000–$20,000 Amazon
8 Novak FX3300-T Electric Fan and Shroud $250–$350 Amazon
9 Novak SGI-5E Speedometer Interface $75–$120 Amazon

The picks, in detail

Novak MMTJ-G3 GM Gen III Engine Mount Kit
Pick 01 of 09

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
Pros

  • purpose-built mounts
Cons

  • welding required
Price: $200–$300
Novak CCLS1C GM Gen III Short Headers
Pick 02 of 09

Novak CCLS1C GM Gen III Short Headers

Short block-hugging headers for a GM Gen III V8 Jeep conversion.

  • short headers
  • GM Gen III
Pros

  • swap-specific routing
Cons

  • engine-specific
Price: $500–$650
Advance Adapters TJ V8 with AX15 LS Gen III/IV Package
Pick 03 of 09

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
Pros

  • drivetrain-specific package
Cons

  • AX15-specific planning
Price: $1,000–$2,000
Howell LS Swap Wiring Harness
Pick 04 of 09

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
Pros

  • purpose-built LS wiring
Cons

  • engine and transmission must match
Novak E-TX41 Crank Position Emulator
Pick 05 of 09

Novak E-TX41 Crank Position Emulator

Tachometer-interface module used with CAN-bus Jeep gauges in GM engine conversions.

  • tach interface
  • GM conversion
Pros

  • gauge integration
Cons

  • application-specific
Price: $175–$250
Advance Adapters 713090 TJ Engine Mounts
Pick 06 of 09

Advance Adapters 713090 TJ Engine Mounts

Advance Adapters conversion mounts listed for 1997–2006 Jeep TJ Wrangler applications.

  • TJ conversion
  • engine mounts
Pros

  • established conversion brand
Cons

  • confirm engine family
Price: $200–$400
Novak LM7 4L60E TJ/LJ Turnkey Powertrain
Pick 07 of 09

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
Pros

  • integrated package
Cons

  • major project cost
Price: $17,000–$20,000
Novak FX3300-T Electric Fan and Shroud
Pick 08 of 09

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
Pros

  • swap-specific cooling
Cons

  • conversion-only part
Price: $250–$350
Novak SGI-5E Speedometer Interface
Pick 09 of 09

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
Pros

  • solves a conversion detail
Cons

  • wiring required
Price: $75–$120

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.

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