I'm going to guess, Your car didn't come of the line with big block and 4 speed.
Improved handling doesn't come from soft parts. Moogs offset upper bushings may be the exception.
Handling comes from springs/torsion bars, stabilizer bar(s), and more modern shock absorbers.
For every tiny but of difference in handling that comes from hard poly bushings, you get as much or more vibration transmitted to the chassis/body/seats. Some of the hard bushings squeak too.
So for my opinion, What a 383 'S' build came with ( K-H front disc brakes and front stabilizer bar ) or better. OEM type rubber bushings all around, plus those offset upper bushings.
