Trail Build Recipe — 35s, Dana 44 Lockers, 4" Lift
This is the standard capable trail build for an early Bronco — not a show truck, not a dedicated rock buggy, but a rig that handles moderate-to-difficult trails reliably and still drives home on the street. Plan on $15K–$35K depending on starting condition and how much you do yourself. The single biggest variable is rust: a solid truck builds at the low end, a rusty one adds $5K–$15K before the fun parts start.
The recipe below assumes a 1969–1977 Bronco with solid floors and a solid frame as the starting point. If the body or frame is rust-compromised, fix that first — building a trail truck on rotten floor pans or rockers is wasted money.
A clean 5.0/302 truck with good sheet metal is the ideal core. Verify the floors, rockers, and frame rails with an awl before you commit a dollar to mods. Rust-compromised structure adds $5K–$15K to this budget before the build even begins, and it's the number one reason these builds blow past their estimate.
- 5.0L HO engine swap if you're starting from an I6 or a tired 302: ~$2,200 with an Edelbrock intake and carb, covered in the 5.0 HO / EFI swap guide
- Shorty headers and 2.5" dual exhaust: ~$650
- Pertronix ignition conversion: ~$90 and the best small dollar on the engine
- Skyjacker 4" complete kit: ~$1,100 with springs, extended shocks, and hardware — see the 4" lift baseline guide for fitment and geometry notes
- Extended stainless brake lines: ~$80, safety-critical, never skip them at 4"
- ARB Air Lockers front and rear: ~$1,160 for both, plus ~$340 for the twin compressor and ~$200 for air line and mounting
- Yukon 4.56 gear sets: ~$680 for both axles, plus $700–$900 for professional setup; match the ratio to your tire per the gear ratio guide
- 35x12.50R15 BFG KO2: ~$1,200 mounted and balanced for five
- 15x8 steel wheels, 4.5" backspacing: ~$500 for five
- Transfer-case and engine skids: ~$500 purchased or fabricated
- Tube rock sliders: ~$400–600 fabricated
The parts list above targets the middle of the market. A budget version swaps the ARB Air Lockers for a Detroit Locker or Truetrac (saves roughly $700-900 combined but loses selectable open-diff mode), uses a mid-tier lift like a Rough Country in place of the Skyjacker (saves $200-300), and holds off on the 5.0 HO swap in favor of tuning the existing 302 (saves $1,800-2,000 but keeps the carbureted engine's cold-start and altitude quirks). That combination lands closer to $10,000-12,000 on a solid core truck. A premium version adds a coilover conversion, full tube doors, and a fully built (not merely regeared) axle on both ends -- $45,000-plus without much effort and closer to a dedicated rock buggy than a trail-and-street truck.
Engine first, so you're not building around a tired powerplant. Then suspension, brake lines, and an alignment. Then the axle regear, and lockers in the same teardown to avoid pulling the diffs twice. Tires last — confirm clearance at full stuff before you buy five of them.
The budget above gets the truck built — it doesn't cover what it costs to keep it running. 35s wear faster than stock-size tires under trail use; budget a replacement set every 25,000-35,000 miles at roughly the $1,200 figure above. The ARB lockers and twin compressor are low-maintenance but not zero-maintenance — inspect the air line fittings and the compressor's intake filter yearly. Fuel economy on a 5.0 HO with 35s and 4.56s typically lands in the 10-13 mpg range, worth weighing before you decide this is a daily driver rather than a trail-and-back rig. Insurance on a heavily modified classic usually runs through an agreed-value classic policy rather than standard coverage — get a quote before you spend the build budget so the number doesn't surprise you afterward.
Why it works
- genuinely capable on moderate-to-difficult trails
- streetable enough for the drive to and from the trailhead
- ARB lockers stay transparent until you switch them on
- builds resale as a clean, sorted driver — not a science project
Trade-offs
- starting condition swings the budget by tens of thousands
- ARB locker installation requires professional axle setup
- 35s on 4.56 with the stock Dana 20 is marginal — 4.88 is preferred for 35s
Tools required
- floor jack
- jack stands
- socket set
- torque wrench
- welder (for skids/sliders)
Parts
| Part | Vendor | Est. price |
|---|---|---|
| Skyjacker 4" suspension kit | Skyjacker | ~$1100 |
| ARB Air Locker front (Dana 44) | ARB | ~$580 |
| ARB Air Locker rear (Dana 44) | ARB | ~$580 |
| ARB twin air compressor | ARB | ~$340 |
| 35x12.50R15 BFG KO2 (set of 5) | BFGoodrich | ~$1200 |
| 15x8" steel wheels, 4.5" backspacing (set of 5) | Various | ~$500 |
| 5.0 HO long block + Edelbrock intake + carb | Various | ~$2200 |
| Hooker shorty headers + 2.5" dual exhaust | Hooker / Various | ~$650 |
| Yukon 4.56 gear sets front and rear | Yukon Gear | ~$680 |
| Skid plates (transfer case + engine) | Various | ~$500 |
Sources
Related
- Stock Restoration Build Recipe
- 4" Suspension Lift — Trail Build Baseline
- Locker Options — Selectable, Automatic, and Limited-Slip
- All Ford Bronco guides & tools
- Browse the full DIY database
Written and maintained by an AZ wheeler and driveway wrencher. How we source guides. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.