Out of curiosity, can any other holden crossmembers be used (other than HR) under an FC so that rack and pinion steer or disc brakes can be used, ie using an LC/J or LH/X crossmember?
The answer is yes and there are some pics on this forum somewhere of Torana front ends fitted to early Holdens. A little more difficult to fit than HR though, you need good welding and fabrication skills to make up and attach the necessary brackets and mounting saddles.
Ken