What diameter torsion bars?

http://www.bigblockdart.com/techpages/torsion.shtml pick your poison.

FYI, these cars were wayyy under sprung from the factory. This was back when the cushy ride was dominant.

The usual fix with a v8 car is to go with a .890-1.03 bar for street, good handling and modern feel, and a slant .810-.870 for drag racing for quick weight transfer. Adjust accordingly.

I just picked up a 1" bar from Just Suspension, $188 including shipping after discount code 'shopalizer'.

If this helps, hit the 'thanks' button and enjoy your weekend!