Drive line phasing question. 70 C20 manual.

[Chris_oz]

Hi all,
On the weekend I replaced the centre bearing (tailshaft support)
I was not thinking and didn't pay attention to the phasing of the uni joints between the front and rear shafts.
I lined them up as I have always done, same as the attached photo,but now I have a vibration that comes in at 25-30mph and stays until 40,the comes back again at 50.
I am sure it's driveline, it didn't have it before.
Is there something different about the chev?
It has the 465 4speed manual and stock 4.57 diff.
I lined up the centre bearing central to the mount.
The workshop manual only has larger truck shafts in it, no smaller trucks shown.
Any tips would be great.