I'm working on another project just now, a 750 hp safe 4-stage auto adaptor, then onto the asa67_stang weapon, with my XC Falcon as a test bed. At the moment, I have let down my Stateside buddy on the adpator, so I can't help untill I 've done what I've promised.
I think fabricated headers are a great idea for specials, but at the moment, its just Will and Import Killers domain.
The best bet it to talk to Mike (Azcoupe) and see if he will allow you to run the item Does10's has. If you wish, you could duplicate one via a NSW firm, or prepay and have Mike send you one ASAP.
The quality is awesome, and it looks trick Jet Hot coated.
There is another option. Get a 2.4 Skyline, 240Z, C or K, 260 Z or C, 280 Z or C exhast manifold, and F66 stick weld six 30 degree ramps to mate it to the stock 2V exhast ports. You then have to cut the out let to clear the engine mount. This allows a cheap version of the factory 200 hp 280ZX-Turbo style manifold to be made. These ran Garrett T03 split pulse blowers in 1982, and are a very good quality casting. It is the same length as the Ford 250 exhast, with the central ports in perfect agreement.
If you used this manifold, it would save a good deal of fabrication.
Here is an LD 28 manifold which I'm converting to fit a cut-off log head. The exhast runner is very close to fouling the engine mount, so it needs to be welded to suit the TO3or TO4 bolt pattern.
But I've said enough!