This is the complete end-to-end assembly of the ASE 2JZ/1JZ to Jaguar ZF 8HP adapter kit — every component, both required modifications, and all three torque specs.
The kit has been shipping for months. This is the first full installation walkthrough.
Watch the full assembly
Why the Jaguar 8HP is worth using — and why the plate has to stay thin
This is the part most people get wrong, and it drives the entire design.
The Jaguar torque converter has four threaded holes, and unlike the Dodge and BMW variants of the 8HP, the Jaguar converter face sits at an almost dead-neutral offset. It is not recessed.
That single difference is why the Jaguar bell housing is slimmer. On the BMW and Dodge units the converter is recessed, so the bell housing has to extend further rearward before it can begin wrapping around the converter body. The Jaguar housing starts tapering down almost immediately.
A slimmer bell housing means less transmission tunnel intrusion, which is the whole reason to choose the Jaguar unit for a JZ swap.
It also constrains the adapter. Clearing the converter spud with a neutral-offset face using a conventional approach would require a plate somewhere around 1¾ to 2 inches thick. That thickness pushes the widest part of the bell housing rearward into the tunnel — undoing the exact advantage you selected the Jaguar transmission for, and driving cost up at the same time. The ASE plate is 1 inch.
What is in the kit
- 1 inch billet adapter plate, machined and surfaced on both sides, with the engine and transmission torque specifications and the part number engraved directly on it
- Billet flex plate with an integrated starter ring gear — no spacers, and the factory JZ flex plate is not reused
- Threaded dowel pins with a broached 8mm hex, designed to be removable and replaceable if one is damaged
- Starter studs in place of bolts
- Starter shim
- 12mm × 1.25 flange head engine bolts, 12-point flex plate bolts, and oversized 12 × 1.75 converter bolts — larger than the 10mm hardware Jaguar uses
The flex plate carries a counterbore that registers on the crank, the same way a factory Toyota flywheel does.
No other Jaguar JZ kit currently offers an integrated starter ring gear with a full billet flex plate and no spacers.
Torque specifications
All three are engraved on the components themselves, so you do not need this page in the shop.
- Engine adapter plate bolts — 50 ft-lb (five 12 × 1.25 flange head)
- Flex plate to crank — 70 ft-lb (eight 12-point)
- Torque converter bolts — 45 ft-lb
The warning that catches JZ first-timers
Toyota drilled the crank bolt holes all the way through. There is a gap behind them.
Install the flex plate bolts dry and engine oil will wick up the threads over time, run down the face of the flex plate, and end up on the floor under the car. Use Loctite, FIPG, or silicone on those threads — Toyota used Loctite, some builders prefer FIPG, and either works. What does not work is using nothing.
Modification 1 — The starter
Because the flex plate carries its own integrated ring gear, the factory starter nose gear has to be relocated.
- Secure the starter against something solid and get a firm grip — it must not walk. Safety glasses on.
- Using a thin cut-off wheel on an angle grinder, cut straight across the shaft. When you break through, the gear will pop up as the C-clip releases it. The splines still run the full length.
- Clamp the gear back down to its resting position, compressing the spring underneath.
- Grind lightly, then weld all the way around, back to the shaft. Tack first, remove the clamp, then finish the weld.
- Drill the threads out of the starter mounting holes so it slides over the studs. This takes under a minute.
An angle grinder or die grinder makes short work of this. A Dremel does not — you will be there all day.
Why studs instead of bolts
The starter sits under the intake manifold with the head on, which makes threading bolts through it awkward — and on a non-OEM transmission you no longer have the factory provisions that made starter access tolerable. With studs you can reach under the manifold one-handed, slide the starter onto the studs, and run nuts down.
This is optional and reversible. Run conventional bolts if you prefer. Either way the starter holes still have to be drilled out, so most people take the studs.
Modification 2 — Trimming the transmission
The converter bolts thread in from the transmission side into the billet flex plate, so you need an access window. Jaguar's factory hole is an inspection port, not a working one, and the oversized converter hardware makes it less usable still.
- Pull the torque converter out and clean up the fluid. Wrap the input shaft.
- Mark using the pre-existing holes as reference — come straight forward from the center of each and connect across.
- Mask it off and cut with an angle grinder or die grinder.
- Clean the edges with a grinding disc so you do not cut your hand on it later.
That window gives enough room to start the threads by hand and enough swing to run a slim ratchet without working in micro-increments.
Assembly order
- Install the threaded dowel pins — no thread locker needed
- Drop the adapter plate over the two Toyota locating dowels; it should sit flush
- Torque the five engine bolts to 50 ft-lb
- Center the billet flex plate on the crank register and torque the eight 12-point bolts to 70 ft-lb — with thread sealant
- Fit the starter shim, then slide the modified starter onto the studs
- Mate the transmission and run the converter bolts to 45 ft-lb through the trimmed window
With the plate and flex plate correct, the transmission mates without needing bolts to draw it together.
Get the kit
2JZ / 1JZ to Jaguar ZF 8HP70 & 8HP45 Conversion Kit — covers both the 8HP70 and the Jaguar 8HP45, which share the same four-bolt converter. The Dodge 8HP45 uses a different converter and is not supported.
This kit is the mechanical adapter only. The 8HP is electronically controlled and will not shift without a standalone transmission controller, purchased separately.
Machined, assembled, packaged and supported in Lakeland, Florida. US-made, no tariffs.