suspension is not something you can tackle like that, you have to address the whole thing. not just front swaybar.
if you were to just update to 1 1/8 inch swaybar you would end up with severe understeer as the front end wouldf be much stiffer than the rear. the fix is then to adda 3/4 inch swaybar to the rear, which reduces the bodyroll and oddly enough stops the understeer and makes for a more cornerwilling car..
but the first, improvement you absolutely categoricly must make is lowereing the upper controllarm wtich involves drilling four holes, and other than the power needed to run the drill is absolutely free!! (this is the exception to the rule that there is no free lunch) Its how shelby made the mustang handle in 65, and it still works today.
send me an email and ill send the the instructions and dimentions.
ive built a 65 coupe once and have helped a friend of mine prepair his for SCCA (actualy ita FIA here in europe) open track raceing.
looking forward to hearing from you