Stock block plus 2.000 sbc rods, longset stroke?

I think you would run into serious trouble fitting a larger stroke than 4.25" into a SBM in terms of crankshaft clearancing.
No matter how small the small end of the rods is. So probably no need to go any shorter with the rod than the standard
6.123 inches, see Brian's reply. Hughes at a time was offering a 426" small block package with a 4.18 stroke in a 360 block...