Learn by doing...(translation...learn from your mistakes, and advise others how to avoid them).

Hooker 2293's are nice long tube steel headers that can be bought at Summitracing.com fairly cheap. These are made for the "Unisteer" rack and pinion setup that bolts to a STOCK tri-5 frame.
As such, they are made with as "spread out tubing" between Cyl 1 and 3.
So not knowing that, I figured I'd order them and use them with my Chevynut C4 frame.
They fit, but the configuration of the #1 tube gets IN THE WAY of where your steering shaft needs to go as it points to the C4 rack.
To fix mine, I just notched and re-welded that up to allow the shaft to go past the #1 header, but its' not the right way to do things on a $100K Nomad build. I may come back later and swap for different headers, but for now...they will work.
Some pics:

IMG_1717.jpg IMG_1718.jpg

So I suggest using Hookers 2292 long length headers instead. All 4 of the tubes (both drivers and passenger sides) angle back consistently, and the #1 tube should by tighter against the block, thus staying out of the way of the steering shaft/C4 rack geometry needed.

hok-2292-1hkr_w_ml.jpg