1 1/8" hollow, or 1" solid are the largest i've heard about for the 1stgen.
i dont know who sells the best, or best price. i know there are several out there which can be ordered over the net. a search engine should turn up lots of hits for you.
the 1 1/8" hollow and 1" solid are supposed to be comparable for handling. the hollow is lighter, but may have a shorter lifespan. i have never seen a broken solid bar on anything. i have seen bent ones, and i've seen quite a few broken hollow bars on production vehicles (from internal rust).
Er, I got my front end kit from Performance Suspension Components here in Phoenix and my front bar is 1-1/8 inch SOLID.
I forgot who made it, but it was one of the better known suspension companies.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI
I just purchased an Addco Sway bar 1" solid and i got it from NPD for $109.00. the thing works great. And i dont know if you've heard of David Pozzi he is like a guru in suspension and brakes for firstgen cars he was the one that recommended the size and the company.
THAT'S who it was mine was from. Hellwig. It might be 1-1/4. PSC's web site said 1-1/8.
2012 Mustang Boss 302 #1918, Competition Orange. FGF replacement 2006 Mustang V6 Pony, Vista Blue. Factory ordered. 2019 BMW X3 (Titled to the wife, but I'm always driving it for her. So I'm claiming it) Old projects, gone but not forgotten: 1967 FB 400, original CA car. After 22 years of work, trashed by the guy who was supposed to paint it. I had to sell it. 1980 Turbo Trans Am 1970 Mustang fastback, 351C 4Bbl, auto 1988 Mustang GT, 5 speed 1983 F-150 4x4, built 302 1994 Chevy K2500 HD 4x4, 454 TBI