This got off into the weeds pretty quickly. If you are really going to run a stock converter, stock ex. manifolds 3.23:1 gears in a 383, forget the single plane manifold. Build as much compression ratio as your budget allows, use a dual plane intake of your choice with a 650-750V.S. carb., and don't over cam it. I have run stock manifolded 383's in 2 different 4 door (66& 68) Newports. Both ran mid 15's at 90ish m.p.h. with less than 8:1 compression,2.76-3.23 gears & stock heads.. I used a cam dynamics 266 energizer(.440" 266 210@.050") and a Crower 260 H.D.P. ( .456"-477" 260-267 212-218@.050). I liked the energizer better as it had tighter lobe sep. and better low end.A 230@ .050 cam and a single plane will be a turd below 3000-3500 R.P.M.