An antiroll bar is spring steel- - - -basically a side to side torsion bar to resist body lean in turns. Going to a much larger diameter bar than original will result in a lot of ride roughness if only one wheel hits a bump or drops into a pothole. It will also transfer a lot of stress to the frame rails ahead of the front suspension crossmember. Handling in turns will also be radically different, so educate yourself on what to expect by pushing the envelope a little where it's safe to do so.
Jerry
You confirm what I told a friend. When you hit a pothole with only one tire, the suspension for that front wheel compresses. The anti-sway bar moves with the suspension but the opposite side suspension resists the movement. So it’s like hitting the pothole with stiffer front springs (like double springs) because both front springs are in play.
That being said, it stays rock solid around hairpin turns. I have a 1.25” C30 bar on my 1965 but the 1 + 1/16” bar on my 1963 is just fine too.
