Does Sway bar worth its weight?

[tanau]

Gents,

My '78 is completely stock and I've seen some sway bar for this car. My car rides nice and tight but tend to drift off a little on highway and at highspeed. It's okay if 40mph or less but anything faster than that, the steering feels very light. So, I was wondering if sway bar, or something else that I can add to make it feel more sturdy.

Thanks much, Tan

[narfire]

An alignment...
All the bushings in good shape....
Ball joints good...
Tie rod ends good....
Correct air pressure in all tires...
Wheel bearings good, no play/clunk
Tires in good shape....
Shocks work properly...
What size tires/ wheels? I have 15 inch with 205's. I notice on the highways that have a crown, I can kind of bounce back and forth.

I should mention if the above is all n good shape, the stock front bar works just fine for normal spirited driving. I've since gone to a 1" front bar and Koni's and notice the improvement but stock is just great as well.