would a rear sway bar be worth the time and expense on a 67 convertible?

what difference would i notice?

 

it will handle better! one of the best mods possible, and get the matching larger front bar also

 

A rear sway bar would be one of the last things I would consider to improve your handling.
Start with the front and work your way back.

 

funny, it was one ofthe first things put on a BOSS 302

 

are you making one cause i have not seen one made for but i have not looked for any interchange

 

Actually, a front and rear sway bar both help with handling, especially hard cornering. The problem is figuring out the desired stiffness of front to rear bars. How stiff is good? Is more better? Anti-sway bars do several things. They reduce body roll in turns. This is good, so more is better if this is all we consider. The ratio of the stiffness of the front bar to the stiffness of the rear bar will have a huge effect on understeer or oversteer. As the stiffness of the rear sway bar is increased understeer will decrease, eventually leading to oversteer. So don't go sticking a massive rear anti-sway bar on a Mustang with a small diameter front anti-sway bar, the result could be dangerous handling (Oversteer is tricky, if you don't correct for it you spin out. Understeer is safer, you just run wide in a turn and you can easily turn in tighter to compensate. Almost all new vehicles are designed to understeer). So, having a 1" bar on front, and a 3/4" bar on the rear is about right.

 

Why? There is already one on the front. One for the rear will greatly improve body roll, and you can update the front. I did just the opposite. I started at the back and moved forward. The car no longre corners like a boat.

 

Sway bars are a tuning device as Soaring stated.
Get the car to drive nice with the suspension, then see where you're at.
Just throwing on a sway bar and saying "I have a such and such front and rear sway bar" isn't the ideal route to a well balanced, good handling Mustang.

 

so you like to have a sloppy rear end?

 

IMHO it's the opposite, but likely just due to different driving styles. Before moving to the land of sun, beaches, and bikini-clad ladies in SoCal, I learned how to drive in the snow in Buffalo, New York with a rear-wheel drive vehicle. Talk about being prone to oversteer in the snow with those tires a-spinn'n! Learned how to correct that one real well without issue. I then, this time on dry pavement, was faced with understeer. As the car was careening toward a guardrail, I desperately tried to correct the understeer by steering more into the turn, but to no avail. Thank goodness the brakes stopped me before the guardrail did! That really scared the bejesus out of me. To this day, I'll take oversteer and spinning out any day over understeer and the inability to turn sharp enough to avoid hitting something.

In any event, safe driving habits should be more important than any of this discussion, unless you're building a track car.