Thanks for advice. By sleeper I meant stock looking engine but with some more oomph to show ricer boys their place. Engine has just a shy over 3 years and I'm reluctant to put in the stroker kit + all that machining once again. I live in Poland and during my rest had lots of problems with mechanics not knowing what mopars are about.
A friend of mine has a 68 charger with the same 383 but running 2330 hughes cam and headers with 3.23 gear and like 27" tires and it feels his motor has 20% power (especially above 60mph).
However I dont want to ruin stock look with these damn headers... which surely would help.

@AndyF - can you post thet racer brown cam specs?

By the way why 3.75 (438) and not 4.25 (496) ? More fun same cost.