Well then why is it different now?

 

My bet is that it isn't different. I am sure that ALL tires on ALL stock suspension classic Mustangs move closer to the top control arm/ball joint when jacked up with the suspension unloaded, even more so when the shocks aren't in place to limit travel.

This just wasn't noticed on disassembly, the OP might have take the wheels of before the shocks, etc.

My son's 64 Falcon had it's front tires(roughly stock dimension tires/wheel combo) resting on the control arm/ball joint just this morning, (on the lift, suspension unloaded, shocks off, and the top of tires touching the ball joints).