1981 hilux build- 3rz fj80 axels+leaf srpings 37's (8 Viewers)

[874runna]

Figured it’s time to start a build thread here on Mud before all this lives only in my head. This project has been in the works for a while, and with parts rolling in, it’s time to document the madness.


The goal is simple: take the light, nimble body of an early Hilux and stuff it with the power, strength, and lockers of an 80‑series — all without breaking my spine on long drives. End result should be a trail‑ready rig by Lone Star Jamboree 2026.

The Rig & Donors

• 1981 Toyota Pickup 4x4 base model (22R long gone, cab off frame).
• Engine: 3RZ‑FE from a ’98 T100. ARP head studs + MLS gasket → turbo planned for Phase 2 with a Haltech Elite 750.
• Axles: ’98 LX450 (FJ80) front & rear, triple‑locked w/ Aisin actuators, already rebuilt w/ upgraded birfs and seals.
• Tires: 37x12.5R17 Mickey Thompson Baja Boss.
• Wheels: Still hunting — 17x9, 6x5.5, 0 to –12 offset.

Suspension

• Front: Rear‑Up‑Front Toyota leafs, Sky’s offset hanger kit.
• Rear: Chevy 63s with Sky’s hangers.
• Shocks: Bilstein 5100s (24‑185509 front, 33‑185552 rear).
• Goal = soft, flexy, highway‑friendly, and capable of clearing 37s.

Steering​

• Toyota IFS steering box (’85–95 Pickup/4Runner).
• Front Range Offroad FJ80 high steer knuckle kit.
• PSC pump + cooler.
• Hydro assist later if I feel the need.

Brakes​

• FJ80 discs all around.
• LX450 master cylinder (possibly booster).
• New 3/16” hardlines + fittings.

---

Build Timeline So Far​

• Sept. 2023: Purchased 1 st gen 4 runner with 3rz swap partially complete
• Sept. 2024: Purchased 1981 hilux pick up. Pulled 3rz +transmission + transfer case.
  
• Oct. 2024: Sold 4 runner shell
• Nov. 2024 pulled bed and started cleaning frame up as well as clean garage.
• January - May 2025: dismantle interior. Start work on 3rz
  
• June 2025: pulled originall 22r, transmission, and transfer case.
  
• July 2025: Pulled cab and cleaned garage again to try yo keep everything as organized as possible (fighting a loosing battle)
  
• August 2025: back too school pause but i will be building a drive way gantry to assist. I am currently waiting on deliveries, and will be starting the removal of axels on the 81 befor i remove axels from my Lx450 I might try to squeez in one more trip with the lx 450 befor i havest the axels

Goals​

Phase 1:

• 3RZ swap completed with single t‑case.
• FJ80 axles installed (leaf sprung RUF/63s).
• Steering & brakes functional.
• Frame cleaned & protected.
• Cab back on, driving on 37s.

Phase 2:

• Turbo 3RZ + Haltech standalone.
• Dual transfer cases.
• Cage, armor, digital dash, and trail extras.

That’s where things sit today. Updates will follow as parts arrive and weekends allow. I’ll try to keep this thread to a weekly log (big or small), so there’s a clear timeline as the FrankenTrück comes to lif

 

[874runna]

so when i was going through the motor I noticed the pistons were makers with a .50 on all pistons does anybody know if this is a standard marking or if this is indication that motor has been previously bored over? honing marks visible on cylinder walls as well. This could be left over from factory am not sure???

 

[Lucille]

Looks like a nice parts list. Converting the 80 axles to leafs is going to be fun. The front axle tubes are a weird shape but can be done with leafs. I just finished mine with basically the same drivetrain but spring under. i set my front spring spacing to 31.5" (its 29" in the solid axle mini trucks). Its low but clears the 40s. Are you going to run the offset 80 rear axle? Keep in mind the factory fuel tank may be in the way unless you run a fuel cell in the back. Looking forward to progress.

 

[874runna]

Lucille. I litterally just found and read your build. I sent you a message. I might need some pointers at some point.

 

[Lucille]

Lucille. I litterally just found and read your build. I sent you a message. I might need some pointers at some point.

Anytime man. What part of TX are you in?

 

[jsnow]

I just did something similar with my 94 Pickup. I used Sky's fullwidth spring hanger, and the FROR knuckles and arms. We ran into clearance issues with the steering and leafs. You would need to sink the perches fairly low to get everything to clear. The Hellfire knuckles are about 1" taller evidently and would have made things easier clearance wise.

On another note, I will be following the build as I have an 83 sitting in my yard waiting it's turn. Stoked to see how yours turns out.

 

[874runna]

Looks like a nice parts list. Converting the 80 axles to leafs is going to be fun. The front axle tubes are a weird shape but can be done with leafs. I just finished mine with basically the same drivetrain but spring under. i set my front spring spacing to 31.5" (its 29" in the solid axle mini trucks). Its low but clears the 40s. Are you going to run the offset 80 rear axle? Keep in mind the factory fuel tank may be in the way unless you run a fuel cell in the back. Looking forward to progress.

well there is my fiirst return as the ubolts for the leafs will need to be flat and i ordered 14" round in a 3.5 radius for the axel but it is square where the perch lands

 

[874runna]

Anytime man. What part of TX are you in?

Dfw.

 

[liveoak]

do you have pictures of the offset rear axle and how the driveshaft looks?

 

[874runna]

do you have pictures of the offset rear axle and how the driveshaft looks?

I have not dont the drive shafts yet. they will be a combination of hilux drive shaft to mate up to the transfer case and my land cruiser drive shaft for the axel side.

 

[874runna]

Week 0 Update – Wheels Mounted on the LX for Testing​

Tires are finally mounted and on the truck. I picked up a set of 37x12.5R17 Mickey Thompson Baja Boss tires and threw them on the LX450 today to get a feel for how they behave on the FJ80 axles before pulling everything for the Hilux build.


Tossed them on in the driveway after work — gave myself a solid eye strain doing it (we're under an ozone warning today, and I probably overdid it), but worth it. They look fantastic on the LX. and shameless plug if anybody needs any thing print or vinyl related , hit me up.

First Impressions:​

• No death wobbles. That's a win.
• Drives pretty solid under 50 mph — smooth, predictable, good feel.
• Above 50? You can tell this isn’t a refined highway cruiser anymore. Not scary, but definitely not Cadillac-spec.
• Steering is heavy, as expected. This was part of the reason I’m going lightweight with the Hilux — same axle strength, half the body weight.

This is a great reality check and gives me something to compare against once those axles are under the Hilux. Can’t wait to see the stance once the cab is back on and the leafs are dialed in.


Also picked up some tall 3-ton jack stands

 

[onemanarmy]

will be following!

 

[874runna]

I just did something similar with my 94 Pickup. I used Sky's fullwidth spring hanger, and the FROR knuckles and arms. We ran into clearance issues with the steering and leafs. You would need to sink the perches fairly low to get everything to clear. The Hellfire knuckles are about 1" taller evidently and would have made things easier clearance wise.

On another note, I will be following the build as I have an 83 sitting in my yard waiting it's turn. Stoked to see how yours turns out.

so this is like the 3 rd time i have read that the hell fire knuckles are a good solution.
I will have to do some more research.

 

[Devils Paw 80]

so when i was going through the motor I noticed the pistons were makers with a .50 on all pistons does anybody know if this is a standard marking or if this is indication that motor has been previously bored over? honing marks visible on cylinder walls as well. This could be left over from factory am not sure???View attachment 3964711

Post #3 in this this thread: Rebuild questions for 1FZ-FE - https://forum.ih8mud.com/threads/rebuild-questions-for-1fz-fe.1366197/#post-16032824
suggests that's OEM marking.
I like the white wheels on the 80. Are those stealth series?

 

[liveoak]

curious why you don't just pull the 80 series body and put the mini truck body on the 80 chassis. stronger frame, axles already installed, coil springs, better wheelbase than a shortbed pickup.

 

[874runna]

Post #3 in this this thread: Rebuild questions for 1FZ-FE - https://forum.ih8mud.com/threads/rebuild-questions-for-1fz-fe.1366197/#post-16032824
suggests that's OEM marking.
I like the white wheels on the 80. Are those stealth series?

yes sir giving the wheel and tire set up a test fit as those axels willl be going under the hilux pertty soon.

 

[874runna]

curious why you don't just pull the 80 series body and put the mini truck body on the 80 chassis. stronger frame, axles already installed, coil springs, better wheelbase than a shortbed pickup.

well I thought about going that route untill my daughter said she liked the Land cruiser so... looks like i will hang on to it and do f250 axels down the road.

 

[874runna]

well I thought about going that route untill my daughter said she liked the Land cruiser so... looks like i will hang on to it and do f250 axels down the road.

well after driving the Lx to work yesterday i noticed a wet spot under the rear axel... i seem to have a leak between the locker actuator and the axel houseing... and i noticed a lot of rust i had not previously seen in the frame. so i dont know how practicle it would be to keep the lx afterall.