340-360 vs 408-414

With LA's tall decks why aren't more people using something like 6.5" rods with a 4" stroke?

Piston would be really short, actually too short, for any kind of street use. Compression distance would be very close to 1" whereas most std rod length 4" stroker pistons are in the 1.4 CD area.

Stock rod length 6.123ish work ok with a 4" crank. IMO, it's something that isn't really an issue with SB mopars. Look over some of the SB chevy stroker combos/rod lengths. Those have some really short rods for the longer stroke set ups.