400 (451) in '68 valaint????

HOUND DAWGER said
Torsion bar upgrade is good for lots of street driveing and I'd say a swaybar is NOT nessisary if you up grade them bars.

True. You don't need them.
It depends on where you do your driving.
If you like hittn those 45 mph curves at 70, like me, then a swaybar is highly recommended.