I got a set for a '69 Grand Prix from PST earlier this year for a factory front sway bar. I wasn't sure of the diameter of the bar (and didn't have a caliper at the time) so I just used an open-end wrench for a nice snug fit (I squeezed the wrench past the "patina" ) to be absolutely sure of the diameter, as the rep at PST said they have all permutations.) Interestingly, the bushings were urethane by default (I don't think they make any other kind?) and came with a little lube - all worked great and without any squeaks.
Sidebar: PST is pretty fair and good to work with (although sometimes hard to reach on the phone.) I installed a complete "super" front end kit from them (non-urethane) in my '65 Coronet in January and it has worked well (and much less $$ than the aggregate of the piece-parts from NAPA with my NAPA discount.) I think they started with Chrysler products and then moved on to other brands later (like Legendary Interiors)
Not a direct answer Hugh, but check with PST (performance suspension technology) they probably have the parts but do not list them by size. I had similar problems ,and although it took some back and forth, solved this some years back. I did not save the data. They are a little disorganized, do not list the bushings directly by size, rather by “application” which did not reach back to 300’s. . I told them to do that, list them by size!! . Fewer sales glossy’s and more data.
The bar thickness is part of a balanced handling design. I would not change it. It can cause under or oversteer. Stiffer in NOT better, always. But new bushings and metal holders can be urethane, stiffer location of original bar, and thus better. Sometimes urethane squeeks. They have ‘graphite lubed urethane” it still squeaked some. I put silicone grease on bar at install , fixed that. … hope the info helps you.
I am working to find the proper bushings for the sway bar in my car (the frame mount). Mine were original, and in dire need of replacement. It appears to be an original sway bar, at just under ¾” in diameter. My mechanic finally came up with an elusive part number (“K7061-MOOG) supposed to be correct, but they came in and are sized for a 7/8” bar.
Does anyone have the proper bushings on hand? The sway bar appears rather insubstantial, is there a recommendation for a source of a beefed-up sway bar that would fit? Then I would need the bushings for it, which would come with it if it were aftermarket.