mmmh...does sound strange.
I wouldn't have thought it possible to have made any changes in the steering head angle, just by changing the yoke.
Its the actual steering head tube that is rotated to adjust the head angle, and you would know if you had done that!
Just offer your old one upto the new one you have and see if the hole centres are the same...I'm sure they will be but it will rule that out.
Sounds to me that something else has been altered without your knowhow as you changed the yoke.
Have you refitted the steering damper? Are the clip-on pins located correctly in the small indentations on the back of the yoke. Did you loosen the stem nut when removing the yoke in any way?
Uhmmmmm....can think of anything else