340 or 440

Ive read several posts here and i know a BB is doable in my 68 Notch. I have a 69 340 x head motor ready to go, i also have a basically stock '73 440. Im currently planning on using the 340. No plans to race. My question to A body guys not planning on hitting the strip, would you go with a BB again if you had the choice? Especially from a fab. fitment perspective. This is a 4spd car, frame connected, no cage or plans for one. Factory K, factory P.S. also, what's the skinny on the smaller 500 series p.s. boxes, 10 pounds lighter, appears to be smaller. Worth the dough ?