Is there really any improvement in handling by switching to offset upper control arm bushings?

My front suspension is about 10 years old with 1" torsion bars in my '65 Coronet.

What kind of change could I expect after a proper alignment?

1 They can be used to attain proper camber on worn cars that will not come into spec with the adjustment cams. 2 If installed in opposite directions can be used to gain more positive caster. If by "proper alignment" you mean factory specs then the offset bushings wouldn't be needed unless your car suffers from 1 above.

My car drives fine. Typical '60's Mopar, kind of numb. I would like to improve cornering, feel if possible.

Can someone explain in simple terms the caster/camber deal? How do these bushings help/hinder?

You might want to start with basic replacements of wear-items first;
New steeringcoupler, replace/rebuild steeringbox, ball-joints/centerlink, lower and upper bushings, and also important, a 'better' idler-arm bushing (polyurethane/nylon). Readjust/replace wheelbearings check/replace tires for uneven wear and only then, do an alignment.
Make sure to do a 'modern' alignment, not one done to '70s factory specs.

Numb feeling is typical for Mopar power steering. There are ways to reduce the numb feeling, like decreasing the power steering pump output slightly through small shims in the regulator valve in the pump. The increased caster deal helps when running todays radial tires. Our old Mopars weren't designed with radials in mind, and as such, the stock range of adjustment in the upper control arms with stock bushings isn't enough to get the caster positive enough for radials to work at their best. Simply put, radials like more positive caster than we can typically dial into a stock vintage mopar front end. Installing the offset bushings helps to move the upper ball joint further towards the rear of the car than is capable with stock bushings, thereby increasing the positive caster.

Thanks guys,

i don't mean to hijack this thread but i'm restoring a 70 340 4sp dart with manual steering. Any idea how they work with manual steering and if I should just install them first or go with oem style first. car last time driven in early 80's did not have problem cornering back then BUT car was radical with E-60 front , G-60 rear. rear also had hi jackers air shocks 110+ psi with 2" extenders
Only problem was on hard braking (KH 4piston) rear end wanted to spin around Anyway any input appreciated thanks moparts

The higher positive caster will increase steering effort. That's nice on a PS application and may be a bit much with manual. Suggest you go with the offset bushings and set caster around 1-2 degrees positive. See how you like it. Adjust from there. Go ahead and increase negative camber.