I'm unfamiliar with the late 50s parts and dimensions, so I can't swag a guess if it would be better, worse, or no different.
It obviously does change its location, but since the upper control arm is still the same length, it has not changed the arc it travels in. The camber curve may be impacted as it moves in this arc. I can see your logic with it moving on this arc as possibly going positive as it transitions through back through its previous neutral point. The length and pivot point of the lower arm can also be a factor in this. It is less than ideal to do this, but how bad is it, I don't have a clue.
The most obvious impact to me is that it will change the instant center locations. These changes will then impact the roll center locations. Is it a radical difference, I don't know. The change from shorter '68-74 pieces to the taller '76-80 pieces does provide some minor improvements on the traditional muscle era cars. Would the change from even taller late '50s parts to shorter late '70s parts make things worse, I really don't know without mapping it out. All the locations of all the pieces impact this so there is not a linear rule that X change produces Y impact as all the inner mounting points and arm lengths on the late '50s cars are a bit different from the late '60s cars.