Single turbo header

I am looking to make around 450 HP boosted on 10# of boost, 318 LA with magnum heads with upgraded springs, air gap intake, upgraded cam. Stock bottom end am planning on 300 NA horsepower. Probably at that power level the 7875 would be the way to go. Years ago I put a turbo on my slant Aspen. It ran good but 2.76 gears held it back. I am running an 8 3/4 with 3.23's in my dart for good street manners.