'71 Duster 440 or 360? Pros and cons
Good one, try to have at least 9:1 compression. I ran 11.60s with the 280 .474, one step below yours. Use a factory high-stall converter and 3.91's. Good intake would be an RPM or a Holley Street Dominator with an 850 Holley dp carb. I ran 2" primary headers, but think it might have been quicker with 1 7/8". This was all done in the late '80s/early '90s...there might be a better intake available for mild 440s now - just don't get some huge runner race manifold.
Spend the money for good machine work, do your homework and find a shop that knows Mopar.