YES 5.9 Magnum manifolds work in early A bodies. Here is exactly how!

It’s not rubbing as far as I can see. I probably do need to adjust the jacket so that it sits more centerline

Ok. It looks pretty tight but it’s hard to tell from the angle of the picture.

It can't be pushed anywhere, its supported on 2 bearings: steering box and steering column unless his steering column is shifted inside? That's why I never got the lower column 'bearing' as it would be the 3rd 'bearing' on the steering shaft.

It can move around quite a bit, the steering coupler provides quite a bit of movement and the top bearing is so thin it provides very little control at the bottom of the column jacket.

And the factory put a bearing at the end of the column jacket on most of the manual steering, stick shift cars. Not to mention the column shift cars that had a bushing and a bearing there that had the additional effect of centering the steering shaft in the column jacket and supporting it with a bearing. I didn’t make up the bearing at the end of the column, I just replaced the really expensive factory bearing and housing with an ER-16 bearing.