TF spring shackles, rear

[Coupeguy2001]

I have the original style spring shackles in my 57's rear, and I made new shackles that were 1 1/2" longer than the originals to drop the rear some more.
My thinking is that somewhere, someone has got to make a car type spring shackle setup for these springs that use a car type rubber shackle.
Could be shooting myself in the foot, but it might ride a little smoother with rubber style instead of the all metal ones that screw into the barrels.

Anyone convert to the rubber type?