i want to say 6 bolt as well, so you won't be the only one with egg on ones face.
most of the literature i have collected about the maxie's say the cranks were hand selected passenger car items that were then given an extra dab of radius on the journals, then were flame hardened.
i did a quick scan of the direct connection and mopar performance engine books, and the only thing mentioned about the cranks was one could install a hemi crank in a wedge block, but then had to use hemi length rods.