What size torsion bars for a 383 in a 75 Dart?

mcodecuda said
In 1967 they used a .087 diameter bar which is the same as what was used in 340 and 360 cars. Later big block cars used a .089 diameter bar which are hard to come by.

I think your decimal place is off a bit.

0.87" and 0.89" slightly less than 1" slightly more then 3/4"

My 67 dart has HD tortion bars.

And measure 0.89