rod length for 3.78 stroke crank

I have a K1 3.79 crank with K1 6.125 rods and an off the shelf forged Diamond piston for a 383 Chevy engine with around a 1.56 comp height. I can double check the specs and part # when I get home. The pistons did have the valve reliefs relocated for use in a SB Mopar, Diamond charged an extra $32 for a set of 8 pistons. This was way cheaper than total custom pistons. The piston I'm using has -30cc for an 8.5to1 CR with Edelebrock heads, I'm running boost.