Will using some longer spring shackles drop my axle lower? Is this a safe thing to do? Feedback would help!!
Get some pictures. Too many variables otherwise. If a standard buggy spring setup,longer shackles won't do anything but bottom out the spring on the top of the axle,rendering the spring useless.
On a Ford with transverse spring offset from the axle long shackles will definitely lower the car. But if they are too long will allow undesirable side sway. A Panhard rod will control this. The last few years of Ford buggy springs had a Panhard rod.
On an old Ford with buggy (transverse) spring, yes, that's how Henry did it in '42-'48. As Rusty noted, you MUST add a Panhard rod (sway bar) if you do this.