Considering the gears & factory stall converter you have, a cam IF kept at a reasonable size will add to the package well. Going to big without adding proper stall will just cause problems. You can do pretty well with a stock converter and small cam. Though I don't know what your intended goal is.
An old member here had a race only Duster but kept the entire package on the Mello side. He lightened the car up a lot! (A key thing!) in his 360, he used a intake duration @.050 of 218. Ran the best of mid 12's. Not bad huh?
I used a simalar cam in a low compression '78, 318 in a 74 Duster/904/3.21 sure gripped rear & stock tires. Basic engine bolt on parts. Ruff tuned, The First outing was 15.14. Not a house on fire! But it did come down into the 14's.
Which is the goal for you?