1HZ Radius Fabrications High Mount Manifold – T3 Flange

The Radius Fabrications 1HZ High Mount Manifold is one of our longest-standing and most trusted products. Designed specifically for Toyota’s legendary 1HZ, 1HD, 1HD-T, 1HD-FT & 1HD-FTE engines, this manifold allows you to mount a T3-flanged turbocharger in a high-mount position for improved performance, clearance, and spool characteristics.

Engineered for Performance

We’ve invested countless hours into refining the design of this manifold. Unlike basic high-mount options on the market, our version features:

• CNC-machined high-mount transition under the turbo flange

• Improved exhaust gas direction and velocity

• Better EGT management and reduced pre-collector EMP

• Stronger, smoother spool characteristics

Every manifold is fully jigged, TIG-welded and then decked after welding to ensure a perfect, flat sealing surface and a precise fit onto your 1HZ head.

If you choose to run a wastegate flange, please note:
You must send the flange to us before fabrication as Radius Fabrications does not supply wastegate flanges.

Product

• Suits Toyota 1HZ, 1HD, 1HD-T, 1HD-FT & 1HD-FTE engines

• T3 turbo flange

• CNC-machined transition for improved flow

• Fully jigged + decked mounting surfaces

• High-quality TIG-welded construction

• 16mm thick flange to prevent warping

• Supports a wide range of turbo upgrades

• Designed and fabricated in Australia

INSTALLATION

Installing the Radius 1HZ High Mount Manifold can be completed by a skilled home mechanic or professional workshop.

Installation Overview

• Remove factory manifold and clean the head’s mounting surface

• Install new manifold with quality gaskets (not included)

• Fit turbocharger to the T3 flange ensuring correct oil feed and drain angle

• Reconnect or modify dump pipe as required

• Reinstall oil/water lines and supporting hardware

• Heat-cycle the manifold and retorque all fasteners

Important Notes

• No gaskets supplied, purchase from your local parts store

• Replace engine studs with longer studs (same diameter) due to our 16mm flange

• Modifying the manifold voids warranty

• Ensure turbo, manifold, and accessories have adequate clearance

FAQ 

What size are the manifold studs?

M10 — unless it is a T2 flange, which uses M8 pitch 1.5 (CT26 uses M10).

Do the 1HD-FT and 1HD-FTE manifolds differ?

No. The 1HD-FT manifold is identical to the 1HD-FTE.

Do you make a 1HDFTE high-mount manifold?

No, we do not fabricate a 1HDFTE-specific high-mount.

Do you manufacture twin-scroll versions?

No, Radius Fabrications does not build twin-scroll manifolds.

Do you supply gaskets with the manifold?

No. Customers must purchase gaskets from their local auto parts store.

How much horsepower can the manifold handle?

• Low mount: up to 200hp

• High mount: up to 280hp

• Merge high mount: 280+ hp

ABOUT THE 1HZ ENGINE

The 1HZ is Toyota’s famous 4.2L straight-six diesel, known globally for its reliability, simplicity, and durability. Found in LandCruiser 80 & 105 Series, it is the engine of choice for touring, off-road, towing, and remote travel.
A high-mount T3 turbo manifold unlocks increased power potential while maintaining dependability, the perfect combination for a tough touring build.