Yes, at $300 a pair, you hate to screw up a good ramhorn. I know it took alot of brazing rod to fill in the gap. I just used a hacksaw and cut right through the manifold, did a pie cut and checked my alignment. It seem to work pretty well and didnt have to make many adjustments before the brazing process. No leaks, but the braze will need painted.
To find someone to "weld" the cast iron may be costly. I had a engine block done once, and that was the last time I would do that, as it became toast. Although not as fragile as an engine block.
Not being able to see the space in front of the steering box, I would mabey turn the flange toward the front of the car, then go forward enough to shoot the gap ahead of the steering box. This is where the old style front dump manifold could come in handy for at least a mock up.
I am glad to be on this site. Good forums, not to many knuckle heads
With any luck I will start on my YBlock 32 Ford project in the next few months. The exhaust is one of my concerns as well.