Once I had my engine (1UZ from a 1991 LS 400) mounted in it's final position, I tried to fit the factory headers and found that the steering rod was in the way.
This left me with 2 options...
Either modify the factory headers as a temporary measure to get the Hilux on the road sooner and then make up some proper headers later, or spend the time now and make up a proper set of headers.
After thinking about it for a while, I decided to make an attempt on some 4 into 1 equal length headers.
I thought a 1-piece flange would make it a lot easier to make the headers so I measured and drew one up on CAD, and then had them water-cut from 10mm steel.
I used about 12 mandral U-bends and aprox 2.5m of 41mm diameter pipe for the primaries and started cutting and tacking the sections into place. This was a very long and drawn out process and involved a lot of re-cutting and welding untill I finally got them all the same length and with enough clearance around the steering, suspension and clutch.
A friend offered to tig the sections together. Once I got the primaries back, I cleaned up the welds and tacked them to the flange while it was bolted to the engine and the engine was in place.
The next trick was to get them out so I could complete the welds and weld on the collectors. This involved lifting the body of the Hilux about 200mm off the chassis and removing the suspension.
I then removed the headers and bolted them to a 100 X 10 steel angle bracket to prevent them from warping during welding. I then fully welded the primaries and collectors and re-fitted them in place to check if it had moved because of the heat caused from welding and was relieved to find that they hadn't moved and that all the clearances were ok.
The primaries are all 39 inches long before entering the collectors and from there will merge into twin 2.25 inch pipes with Lukey turbo mufflers on each pipe. They will then merge into a single 3 inch tailpipe.
This has been a nightmare of a job and ended up taking me a lot longer than I initially thought but I think the final result was worth the effort.
![Headers2.jpg Headers2.jpg](https://www.lextreme.com/forums/data/attachments/12/12663-36b79ce8e5043bce7e06f888d7bb9f4d.jpg?hash=Nrec6OUEO8)
Primaries tig welded together & ready to be mig welded to the flange.
![P1010021.jpg P1010021.jpg](https://www.lextreme.com/forums/data/attachments/12/12664-db34ca88ecea265ae95c0462c6720080.jpg?hash=2zTKiOzqJl)
And finally the finished product.
![P1010022.jpg P1010022.jpg](https://www.lextreme.com/forums/data/attachments/12/12665-f509b78e96fee2bb8423b98ca6785e25.jpg?hash=9Qm3jpb-4r)
This left me with 2 options...
Either modify the factory headers as a temporary measure to get the Hilux on the road sooner and then make up some proper headers later, or spend the time now and make up a proper set of headers.
After thinking about it for a while, I decided to make an attempt on some 4 into 1 equal length headers.
I thought a 1-piece flange would make it a lot easier to make the headers so I measured and drew one up on CAD, and then had them water-cut from 10mm steel.
I used about 12 mandral U-bends and aprox 2.5m of 41mm diameter pipe for the primaries and started cutting and tacking the sections into place. This was a very long and drawn out process and involved a lot of re-cutting and welding untill I finally got them all the same length and with enough clearance around the steering, suspension and clutch.
A friend offered to tig the sections together. Once I got the primaries back, I cleaned up the welds and tacked them to the flange while it was bolted to the engine and the engine was in place.
The next trick was to get them out so I could complete the welds and weld on the collectors. This involved lifting the body of the Hilux about 200mm off the chassis and removing the suspension.
I then removed the headers and bolted them to a 100 X 10 steel angle bracket to prevent them from warping during welding. I then fully welded the primaries and collectors and re-fitted them in place to check if it had moved because of the heat caused from welding and was relieved to find that they hadn't moved and that all the clearances were ok.
The primaries are all 39 inches long before entering the collectors and from there will merge into twin 2.25 inch pipes with Lukey turbo mufflers on each pipe. They will then merge into a single 3 inch tailpipe.
This has been a nightmare of a job and ended up taking me a lot longer than I initially thought but I think the final result was worth the effort.
![Headers2.jpg Headers2.jpg](https://www.lextreme.com/forums/data/attachments/12/12663-36b79ce8e5043bce7e06f888d7bb9f4d.jpg?hash=Nrec6OUEO8)
Primaries tig welded together & ready to be mig welded to the flange.
![P1010021.jpg P1010021.jpg](https://www.lextreme.com/forums/data/attachments/12/12664-db34ca88ecea265ae95c0462c6720080.jpg?hash=2zTKiOzqJl)
And finally the finished product.
![P1010022.jpg P1010022.jpg](https://www.lextreme.com/forums/data/attachments/12/12665-f509b78e96fee2bb8423b98ca6785e25.jpg?hash=9Qm3jpb-4r)