I have a 1970 Duster (originally a slant six) that will be upgraded to a 340 with a 727 trans and 8 3/4 rear axle (possibly 3.91 gear). A majority of the time, the Duster will be driven on the street to shows/cruises (maybe strip at Mopar events).

What type of rear leaf springs would you install on the vehicle? OE Leaf Springs: P4510268 and P4510269 or Competition Leaf Springs - Super Stock: P3412002 and P3412003?

With regard to the front torsion bars:
P5249148 - Torsion Bar, 0.810" Diameter for A-Body
P5249150 - Torsion Bar, 0.890" Diameter for A-Body
P5249151 - Torsion Bar, 0.920" Diameter for A-Body

*If vehicle was used more for drag racing (with a stroker 340 kit), what would be your recommendations?

Thank you in advance for your feedback!