budget street motor 360 or 383 for 71 duster

I love 383's, but in A-bodies, unless You're using the B engine framework to go BIG, it ain't hard to reach Your stated goals w/a 360. Not to mention You remove more
weight if You choose to go aluminum heads & intake on a SB than a BB. OE SB heads & intakes are HEAVIER than OE B/RB ones. As mentioned, building a very common
these days 408 stroker will make it cake for You.