What torsion bars and leafs on a 74 Duster?
My 68 Barracuda came with the heavey duty \6 suspension which was the light duty small block v8 torsion bar and 6 leaf springs. With new KYB Gas shocks the car handled very well.
Last winter when I did the disk brake swap I upgraded to the big block A-body torsion bars up front. The car still handles very well and bottoms out less on large bumps and dips.
This winter I am installing a 360 and plan to stay with the same torsion bars but I have a v8 spool mount K-member and will use a larger than stock diameter late style sway bar.